Sanders-Warren tension dominates final debate before Iowa caucuses

As candidates greeted each other onstage after the debate, Warren shook hands with Biden and then moved toward Sanders and appeared to avoid a handshake offered by Sanders, instead clasping her hands together. The two appeared to engage in a brief, heated conversation as Steyer hovered nearby.

Steyer told CBS News' Ed O'Keefe and Caitlin Huey-Burns after the debate that he "didn't really hear," but that it looked like they were trying to "figure out something between the two of them."  

"I was really just trying to say good night" to the two, Steyer said.

The interaction capped a contentious debate between the two senators, who have long had a friendly relationship. Warren said just a day ago that Sanders, in a 2018 conversation about taking on President Trump, told her he didn't think a woman could win. Sanders has vehemently denied this, including during the debate.

"Well, as a matter of fact, I didn't say it. And I don't want to waste a whole lot of time on it because this is what Donald Trump and some of the media want," Sanders said.

However, moderator Abby Phillip then asked Warren if she disagreed with Sanders' 2018 comments, acting as if it had been confirmed that Sanders had made the remark.

"I disagree," Warren responded. "Look at the men on this stage. Collectively, they have lost 10 elections. The only people on this stage who have won every single election that they've been in are the women."

Candidates made their final pitches to Iowans on why they were the best equipped to face Mr. Trump in the general election. Klobuchar highlighted her bipartisan bona fides and her ability to unite more moderate members of the party.

"We need a candidate who is actually going to bring people with her. I have won every race, every place, every time," Klobuchar said.

Steyer compared Mr. Trump to bullies in team sports, saying that he was "basically kicking Americans in the face." He argued that he would make a "good teammate" and told viewers that "together, we can change the world."

Buttigieg appealed to viewers who were "exhausted by the spectacle of division" at the debate, as well as voters of color who are "feeling taken advantage of by the party."

"This is our moment. This is our one shot to defeat Donald Trump, and to do it by such a big margin that we send Trumpism into the dustbin of history, too," Buttigieg said.

Warren used her closing statement to address some of the topics not discussed during the debate, including gun violence, violence against transgender individuals, and the black maternal mortality race. However, she said, she was filled with hope because it is "our moment."

"Hope and courage. That is how I will make you proud every day as your nominee and as the first woman president of the United States of America," Warren said.

Sanders complained that the debate did not adequately address how to lift Americans out of poverty.

"It's been a good debate, but we haven't asked the biggest question," Sanders said, echoing Warren's closing statement. "This is the moment, when we have got to think big, not small."

Meanwhile, Biden reiterated his argument that this election is about "fundamental human decency."

"Character is on the ballot this time around. The American character is on the ballot," Biden said. "We have to restore America's soul."

Regarding the effects of climate change, Buttigieg was asked what he'd do about farms and factories that cannot be relocated.

"We've got to act, yes to adapt … but we also have to ensure that we don't allow this to get any worse," Buttigieg said, before noting the federal government needs to reach out to skeptics and those who might be affected.

Steyer, who launched his campaign on climate change, reiterated that he would declare a national emergency over climate change on his first day in office.

"I have a history of over a decade of leading the climate fight successfully," he said.

Warren, asked how she would make environmental protections more permanent, said she would roll back the environmental changes Mr. Trump has put in place and stop offshore drilling. Climate change isn't new, Warren said, insisting that the next administration needs to fight the influence of industry.

Klobuchar views natural gas as a "transition fuel," she said, while Sanders, who disapproves of natural gas, shook his head.

"When we do this, we have to make sure that we make people whole and when we put a tax on carbon, which we will do … then we have to make sure that money goes back to the people that will be hurt by it," Klobuchar said.

Sanders said he'd introduce legislation declaring climate change a national crisis.

"We have got to take on the fossil fuel industry and all of their lies and tell them that their short term profits are not more important than the future of this planet," Sanders said.

Biden called for U.S. investment in green-friendly infrastructure. Biden insisted the U.S. can turn the green revolution into new jobs.

Biden disputed that it would be harder to run against Mr. Trump if he were acquitted by the Senate in an impeachment trial, saying that impeachment was a constitutional necessity aside from the election.

"It's irrelevant. There's no choice but for Nancy Pelosi and the House to move," Biden said. He slammed Republicans for smearing his "surviving son," Hunter Biden, and telling "lies" about his family.

Klobuchar, who as a senator will be one of the jurors in the upcoming impeachment trial, said that she did not believe Mr. Trump would be "emboldened" by a potential acquittal.

"This is a decency check on our government. This is a patriotism check," Klobuchar said.

Steyer, who spent millions of dollars on a campaign to urge the impeachment of Mr. Trump, said his money would not have been wasted if the president is acquitted.

"Standing up for what's right is always worth it," Steyer said.

Warren sidestepped a question about how the impeachment trial would prevent her and other senators from hitting the campaign trail.

"Some things are more important than politics," Warren said.

Following up on the cost of childcare, differences between the candidates about whether college should be free emerged.

Sanders believes college should be free and student debt should be canceled. Buttigieg doesn't think students from wealthier families should be able to attend college for free.

Klobuchar said the focus shouldn't only be on the cost of college, but on college alternatives and job training.

"I think some of our colleagues who want free college for all aren't thinking big enough," Klobuchar said. She pointed to the rising need for people to be home health care workers and nursing assistants. We're not going to have a shortage of MBAs, she said. We're going to have a shortage of plumbers.

Steyer, the wealthiest candidate on stage, was asked whether his children should have gone to college for free, since he's a billionaire

"No," Steyer responded simply.

 Buttigieg fielded a question about how he would ensure that parents were able to access affordable childcare.

"This is happening to folks at every level of the income spectrum," Buttigieg said about the struggle to access childcare, explaining that he supports government subsidies for health care.

Warren drew on personal experience, saying that she nearly quit her job as a young university professor because she struggled to find affordable childcare for her two young children and was able to keep it because an aunt helped her out. 

"I have a two-cent wealth tax so that we can cover childcare for all of our children," Warren said.

Sanders said that the U.S. needed to guarantee childcare for its citizens.

"Our current childcare system is an embarrassment. It is unaffordable," Sanders said. "We need to fundamentally change priorities in America."

Biden also drew on his personal experience as a single father after the death of his wife and young daughter early during his tenure as a senator, and he said he supported free universal infant care.

"Bernie's right, we have to raise the salaries for people who are doing the care," Biden said.

Health care continues to be a top issue for voters in Iowa. Warren was forced to answer questions about the cost of Medicare for All, while Klobuchar and Buttigieg called for more moderate plans that, while they would cost money, would cost less than the pricey single payer plan.

But Warren continued to defend Medicare for All and insisted she'll also lower the cost of widely-needed prescription drugs.

"What we need to do is make the commitment that we know where the money comes from," Warren said.

Klobuchar said she's dedicated to paying down the national debt. Buttigieg pegged the cost of his plan at perhaps $1 trillion, not tens of trillions of dollars.

Biden stood by Mr. Obama's signature health care law, insisting the next president needs to expand on that health care overhaul.

Asked whether the government should be able to manufacture drugs, Klobuchar said she's "open" to the possibility. But she also wants to look into bringing in drugs from other countries.

The campaign Twitter account for presidential candidate Mike Bloomberg — who is not attempting to qualify for the debates because he is not taking donations — posted dozens of humorous, sometimes surreal tweets as a form of viral counter-programming to Tuesday's debate.

"We promised to tweet stuff. We promised fun stuff. We promised the best stuff. Here we go," the Team Bloomberg account tweeted before the debate began. As the other candidates sparred onstage in Des Moines, Iowa, the Bloomberg account posted memes, jokes and a series of joke "#BloombergFacts" often poking fun at the candidate himself. "Spot the meatball that looks like Mike," said one Team Bloomberg tweet.

Bloomberg told CBS News in December that he believes the debates don't "really matter" and the public is not focused on them.

Moderators turned to a familiar subject for the Democratic debates, asking Sanders how he intended to pay for his "Medicare for All" proposal. Sanders argued his plan would end up costing Americans less in the long run, but would require higher taxes. Biden argued Sanders needed to be more explicit about the price tag for Medicare for All.

"I think we need to be candid with voters. I think we need to tell them what we're going to do and what it's going to cost," Biden said.

Klobuchar pointed out that many Democrats in the Senate and across the country don't support Medicare for All, but instead prefer a more moderate plan.

"This debate isn't real," Klobuchar said, dismissing Medicare for All. The "real debate," she argued was about treating mental health and ensuring long-term coverage for Americans.

Warren segued to talking about Mr. Trump, and his opposition to the Affordable Care Act, saying it was more important to defeat Mr. Trump than to argue about health care.

"I'll take our side of the argument any day. We're going to beat him on this," Warren said.

Steyer expressed weariness with this line of questioning, saying the argument over Medicare for All had been adjudicated on the debate stage multiple times.

"We've had this conversation on this stage so many times," Steyer said.

Nearly one hour into the debate, debate moderators injected the bombshell story about Sanders and Warren. On Monday, CNN reported Sanders had told Warren in 2018 that a woman couldn't win the presidency. 

"Well as a matter of fact, I didn't say it," Sanders said, denying the story.

Sanders pointed out that he has long supported Warren. 

Warren said she disagreed with Sanders' reported claim, before taking a swipe at the men on stage.

"Look at the men on this stage, collectively, they have lost 10 elections," she said to laughs and cheers from the audience. "The only people on this stage who have won every single election that they've been in are the women."

Sanders interjected, saying he had beat an incumbent Republican. Warren asked him when. Sanders said it was in 1990. 

"Wasn't it 30 years ago?" Warren said. 

Sanders went on to say that he of course believes a woman can win. 

Sanders discussed his opposition to the U.S.-Mexico-Canada Trade Agreement (USMCA), which the Senate is set to approve as early as this week.

"We could do much better than a Trump-led trade deal," Sanders said, adding that the deal did not do enough to address workers rights. "The heart and soul of our disaster trade agreements...is that we have forced American workers to compete against people in Mexico, in China, elsewhere, who earn starvation wages."

He also said that he would not vote in favor of a trade agreement that does not address climate change.

Warren argued she supported USMCA because it was an improvement on NAFTA, even if it wasn't perfect.

"We have farmers here in Iowa who are hurting, and they are hurting because of Donald Trump's initiated trade wars," Warren said. "This new trade deal is a modest improvement."

Sanders disagreed, saying that it was not enough to approve a deal which only made small improvements.

"If this is passed, I think it will set us back a number of years," he said.

Unlike Sanders or Warren, Klobuchar touted her support for USMCA, saying she was proud to stand alongside progressive workers' advocates like Senator Sherrod Brown.

"I am glad that these improvements were made," Klobuchar said. "I think we need a big trading bloc with North America to take on China."

Asked if he would meet with North Korea without any preconditions, Biden gave a flat answer: "No," at least, not now. The former vice president criticized Mr. Trump's favorable treatment of North Korean leader Kim Jong Un.

"We gave him everything he's looking for: legitimacy," Biden said.

Biden said Mr. Trump's glowing treatment of Kim and mentioned his touting of "love letters" from the dictator.

Steyer, whose focus has largely been on environmental issues and domestic issues, gave a similar answer to Biden.

Moderator Abby Phillip asked Buttigieg whether he would allow Iran to obtain a nuclear weapon. Mr. Trump has promised that Iran will not become a nuclear power as long as he is in office.

"Ensuring that Iran does not develop nuclear weapons will of course be a priority," Buttigieg said. "Our security depends on ensuring that Iran does not become nuclear." Buttigieg blamed the current situation in Iran on the Trump administration's abandonment of the Iran nuclear deal.

Klobuchar said that, as president, she would negotiate with Iran and allies to form another deal to replace the original Iran nuclear deal.

"You have to have a president that sees this as a number one goal ... and then you have to get an agreement in place," she said.

Blizter asked about candidates what they would do to grapple with the problems in Iran and the Middle East.

Former Vice President Joe Biden, who has been touting his foreign policy experience in his ads, said America is "now isolated." He said he would leave small numbers of troops in the Middle East. Biden said a few minutes later  the U.S. needs to coordinate coalitions with other countries to counter terrorist entities in the Middle East.

Klobuchar said she's long wanted to withdraw most troops from Syria.

Warren took a slightly different tack, saying the U.S. has been trying too long to solve problems with military might, instead of looking for diplomatic solutions.

"We need to get our combat troops out. They are not helping create more safety for the United States or the region," Warren said.

Biden then jumped in to say there's a difference between combat troops and special forces. Some U.S. presence needs to stay in the Middle East, the former vice president argued.

Buttigieg, who frequently cites his military experience, pointed back to Mr. Trump. The very president who said he would end endless wars now has more troops going to the Middle East, the former Indiana mayor said.

Sanders, who has consistently opposed war in the Middle East, echoed Warren in saying the U.S. needs to seek diplomatic solutions.

Buttigieg seized the moment to call for a new Authorization for the Use of Military Force. That authorization "needs to be replaced," he said.

Warren, too, called for a new AUMF. No one wants endless wars, Warren noted — the key is having a strategy to get out of endless wars. Every so often there's a new leader who calls for turning a new corner in wars in the Middle East, Warren said.

"We've turned the corner so many times we're going circles in these regions," she said.

The first question of the debate was focused on foreign policy, coming after after tensions with Iran escalated earlier this month. Moderator Wolf Blitzer asked the candidates why they believed they would be the best commander in chief.

Sanders argued that his good judgment was proven when he voted against the 2002 Authorization for Use of Military Force (AUMF) in Iraq. Biden, who did vote to authorize the war in Iraq, countered: "It was a mistake, and I acknowledge that." However, Biden also noted he was chosen as vice president by former President Obama, who had opposed the war in Iraq from the beginning.

Sanders suggested that he, unlike Biden, was not fooled by the Bush administration's insistence that there were weapons of mass destruction in Iraq.

"Joe and I listened to what Dick Cheney and George Bush and Rumsfeld had to say. I thought they were lying," Sanders said. However, Biden argued that as vice president, he actually had experience in bringing troops home from Iraq.

Sanders also tied the conflict in Iraq to that in Vietnam.

"The two great foreign policy disasters of our lifetimes were the war in Vietnam and the war in Iraq. Both of those wars were based on lies," Sanders said.

Klobuchar argued that the candidates should be focused on ensuring the U.S. did not enter a needless conflict with Iran.

"Donald Trump is taking us pell-mell towards another war," Klobuchar said.

Meanwhile, Buttigieg brought up his perspective as a veteran and the youngest person on the stage.

"There are people now old enough to enlist who were not alive for some of those debates," Buttigieg said of wars entered after September 11, 2001. He added that the next president would be confronted with national security challenges different from those of the past, including cyber and climate threats. The next commander-in-chief will need to have a view to the future, as well as to readiness.

Warren tied her anti-corruption message to her answer on why she would be an effective commander-in-chief, arguing that the U.S. was spending too much on defense.

"We have a problem with a revolving door in Washington between the defense industry and the Department of Defense and the Pentagon. That is corruption, pure and simple," Warren said.

Speaking at a rally in Milwaukee on Tuesday evening shortly before the Democratic debate, President Trump weighed in on the latest spat between Sanders and Warren. Warren claims that Sanders told her in 2018 that he didn't think a woman could win the presidency, which Sanders has denied.

Although Sanders is a "nasty guy," Mr. Trump said, he did not believe Sanders would say that a woman could not win.

"I don't believe that Bernie said that. I really don't," Mr. Trump said. Of a woman winning the election, Mr. Trump said with a laugh: "That could happen."

One of the top bundlers for Harris' erstwhile presidential bid will be helping Joe Biden's fundraising efforts as the Democratic primary field narrows.

Michael Kraut of Kraut Law Group in Los Angeles raised more than $100,000 for the Harris campaign before she exited the race in December.

Kraut told CBS News he was contacted by multiple Democratic presidential campaigns after Harris ended her bid, including Elizabeth Warren's and Cory Booker's campaigns, but ultimately decided to support Biden.

"We know where his heart is," Kraut said of Biden. "We know where his mind is, and we know what he holds as the values to the United States."

Not only does he plan to raise funds for Biden, he also brings a network of potential donors tapped by the Harris campaign. And he indicated he's also considering traveling to early states to help canvas.

Biden's campaign news of the apparent Russian hacking "proves that both Donald Trump and Vladimir Putin understand the true stakes of this election."

Biden is airing a new ad on Tuesday in Iowa called out the president's continued focus on him. "He's got Joe Biden on his mind," said the ad.

Polling consistently shows voters believe Biden is best-positioned to defeat the president in the general election. That has other Democratic candidates — and Republicans — trying to raise doubts about the former vice president.

While Sanders has been engaged in a feud with Warren, he tweeted on Tuesday that he doesn't think Biden's record will "bring forth the energy" to defeat the president.

At the Capitol, Republican House Minority Leader Kevin McCarthy argued that Biden will have an unfair advantage over Sanders and other senators running for president once the impeachment trial gets underway.

"The only rightful thing of Joe Biden is to make a pledge not to campaign while Bernie Sanders cannot," McCarthy said.

With the Minnesota senator attracting support ranging from 6%-8% in the latest Iowa polls, Amy Klobuchar is hoping to shore up what her campaign is calling the "Klomentum" of the last debate. She's in about fifth place, behind the four front-runners, despite strong performances in the debates. 

Her campaign said it would prioritize TV and radio ads and try to get her back to Iowa as much as she can as she faces what could be a sustained absence from the trail as she attends the president's impeachment trial in Washington. 

"I feel she had a breakout moment at the last debate and that sold me," one person who plans to caucus for Klobuchar told CBS News.

As Biden has been touting his foreign policy experience amid growing tensions with Iran, Klobuchar has been highlighting her opposition to the Iraq War.

—  Bo Erickson 

The Warren campaign has been telling high-level allies today that the Massachusetts senator wants to deescalate her feud with Sanders over whether he had told her that a woman couldn't win the presidency, CBS News confirms. BuzzFeed first reported that Warren's campaign is urging supporters not to accuse Sanders of sexism and wants to move on.

Instead, Warren would prefer to refocus on resuming their progressive arguments against the moderates in the race at the debate tonight.

—  Zak Hudak and Ed O'Keefe

All eyes will be on how Sanders and Warren interact after CNN first reported Monday that Sanders in 2018 told Warren a woman couldn't win. Warren has roughly confirmed the crux of the story on the record, while Sanders' campaign has disputed it. The two progressive candidates have largely refrained from criticizing each other up to this point, but Warren has been lagging in recent polls and time is running out before the first voting contests. 

Then there's the question present at every debate — can Biden deliver a strong performance with minimal, verbal flubs? A Monomonth poll published Monday showed Biden leading the field at 24%, several points ahead of his closest competitors, and he needs to keep or improve his standing to win. 

There's another glaring matter in this debate — every candidate on stage is white. The all-white debate stage comes after Julián Castro, the only Latino candidate in the race, dropped out on January 2 and Cory Booker ended his campaign on Monday. The other Democratic candidates of color in the race, Andrew Yang, Deval Patrick and Tulsi Gabbard, failed to qualify for this debate. 

After Deval Patrick bashed the debate for its lack of diversity, party chairman Tom Perez struck back, telling CNN Tuesday that "we've set a really remarkably inclusive and frankly low bar throughout the campaigns."

Patrick said in a statement that the debates are not "representing the Nation" and have become "an end in themselves."

He compared them to "an episode of reality TV with candidates paying more attention to polling numbers and donations than issues and people."

None of the six candidates on stage tonight has "ever been questioned about their citizenship," he noted, or has experienced "fear for their safety when pulled over for a routine traffic stop."

While Perez said he may miss having candidates like Kamala Harris and others in the field, he told CNN, "We can't change the rules midstream because there's a candidate I wish were on but didn't make the debate stage."

— Reporting by Nikole Killion 

Mike Bloomberg won't be on stage, but he has a new digital ad up on YouTube and the front page of The Washington Post reminding Americans that the multi-billionaire is not taking "a dime" from anyone for his presidential campaign, and as a result, the Democratic Party won't let him participate in the presidential debates. 

"The party rules prevent me from debating," he says in the ad. "If they change the rules, I'd be happy to join it."

In the meantime, he says, he's traveling the country and making the case that "Donald Trump has to go."

–Tim Perry