Election Day 2018: Voters go to the polls as control of Congress hangs in the balance

Find live updates and latest vote tallies here. Updates from earlier in Election Day appear below as they happened.

Millions of Americans are heading to the polls Tuesday to select their representatives to the 116th Congress, with the balance of power in Washington hanging in the balance. All 435 seats in the House are up for grabs, along with 35 Senate races and 36 gubernatorial contests.

Democrats face an uphill climb in wresting control of both chambers, but they appear poised to take control of the House. The last CBS News Battleground Tracker estimated Democrats would win 225 seats in the House under one scenario, more than the 218 needed to take control. That same scenario showed Republicans winning 210 seats. But that estimate has a margin of error of plus or minus 13 seats on each side, meaning the final balance will depend on who shows up to the polls and who doesn't.

Republicans have a much better chance of keeping control of the Senate, where several incumbent Democrats are defending their seats in states President Trump won in 2016. Democrats need a net gain of two seats to win a majority.

Follow along throughout the day for live updates as voters cast their ballots, and tune in to CBSN tonight for special election night coverage.

• Watch special election coverage live on CBSN on fuboTV. Start a free trial.

Beyonce endorses Beto O'Rourke

Beyonce issued a last-minute endorsement to Beto O'Rourke on Instagram Tuesday evening.

"I'm feeling grateful for everyone before me who fought so hard to give us all the right to have a voice. We can't voice our frustrations and complain about what's wrong without voting and exercising our power to make it right," she wrote on Instagram. "Sending you all love and positivity on this happy voting day!"

The text was accompanied by photos of her wearing a "Beto" hat. Several celebrities have been seen sporting the "Beto" hat, such as LeBron James and Willie Nelson.

Beyonce has a large fan base known as the "Beyhive." If there were any Texas voters who were waiting for an endorsement from Beyonce to cast their vote, now they have their justification.

Early exit polls show Trump a major factor in vote

Early CBS exit polls suggest that President Trump was a factor that significantly affected voting for the House.

One in four of those casting a ballot, 26 percent said they did so to support him; 39 percent did so to oppose him; and 33 percent said this election isn't about him.

Only a minority of those voting today approve Mr. Trump's job performance. The level appears similar to his ratings among the general public overall in recent months. It is also similar to the ratings for former President Obama in the 2010 midterm election, in which Republicans captured majority control from Democrats.

Voters reported that their number one issue in this election was health care--mentioned by just under half of those surveyed. Health care was mentioned by almost twice as many voters as the next most common issue, immigration.

Voters are feeling better about the state of the economy than they have since before the great recession of 2008. More than two-thirds rate the economy as good, compared to 36 percent only two years ago.

However, only one in five voters selected the economy as the most important issue in the election this year, perhaps limiting the benefit of this issue for the ruling Republican Party.

-- David Jones, professor of political science at Baruch College, City University of New York

Medicaid expansion, marijuana on the ballot

Voters nationwide are weighing in on more than 150 ballot measures. People in Idaho, Nebraska and Utah are voting on Medicaid expansion under the Affordable Care Act.

Some state Republican leaders oppose the move. If it passes, it would cover an estimated 325,000 low-income residents.

North Dakota and Michigan are voting on whether to legalize recreational marijuana. Voters in Utah and Missouri are deciding whether to make medical marijuana legal.

Washington state could pass one of the toughest gun-safety laws in the nation. The age limit to buy an assault rifle would increase from 18 to 21, and there would be a 10-day waiting period for purchases.

San Francisco may authorize a tax on businesses that make more than $50 million a year. The money would fund housing for the homeless.

Some business leaders, like Twitter CEO Jack Dorsey and gaming billionaire Mark Pincus, oppose the initiative. Salesforce CEO Marc Benioff spent $8 million to back the proposal.

Parkland dad makes emotional plea to vote

The father of a 14-year-old girl who was killed earlier this year in a high school shooting is urging people to vote "Democrat across the ballot" and in favor of gun safety. In one social media post, Fred Guttenberg made his plea by posting a picture of his daughter's grave.

Officials blame touch screens after voter complaints

In South Carolina, some people in Richland County said their voting machines malfunctioned. According to CBS affiliate WLTX, the final voting submission page did not reflect people's intended votes.

Some people said that their votes were flipped. Officials believe that a calibration issue with the machines' touch screens was to blame and encouraged voters to review their final page before submitting it.

"The machine is not changing your votes," county elections director Rokey Suleman told WLTX. "There's no boogeyman in the machine. All it is is it's a hardware issue, and notify the poll workers who are there, and the poll workers will walk you through how to correct the problem."

Trump gives late endorsement in N.J. Senate race

President Trump gave the Republican nominee in New Jersey's Senate race an Election Day endorsement. Bob Hugin is challenging Democratic Sen. Bob Menendez.

The endorsement may not be what the former pharmaceutical CEO wants on the top of New Jerseyans' minds before they go into the voting booth. In one of Hugin's television ads, he said he'd stand up to Mr. Trump if elected.

Wave of diverse candidates on the ballot

Across the country, there is a wave of diverse candidates on the ballot fighting to be a "first," CBS News correspondent Paula Reid reports. In Arizona, the state will get its first female senator -- Republican Martha McSally and Democrat Kyrsten Sinema are duking it out for the coveted seat.

Voters in Georgia could make history by electing Stacey Abrams as the nation's first black woman to be governor. In Vermont, Christine Hallquist could become the first elected transgender governor.

Minnesota and Michigan may pave the way for the first Muslim women to Congress with candidates Rashida Tlaib and Ilhan Omar. While these candidates are Democrats, Republicans may also break ground.

In California, Republican voters could put the first Korean-American woman, Young Kim, in Congress.

Taylor Swift urges fans to vote

Once known for her political silence, Taylor Swift is continuing her crusade to get fans to the polls on Election Day. In October, the pop star reportedly caused a spike in voter registrations both nationwide and in Tennessee when she spoke out on Instagram, and on Tuesday, she reminded fans to vote.

What's bringing young people to the polls? (Or keeping them away.)

A record number of young voters are expected to show up at the polls on Election Day. A Harvard University study estimates that 40 percent of people under 30 will be voting.

Fifty-four percent of young Democrats said they are "definitely voting." That's compared to 43 percent of young Republicans.

CBS News asked young people across the country what's bringing them to the polls or keeping them away. Some of their answers are below.

• Mikaela, 21, NYU student: "I'm voting because where I'm from in Texas it's an extremely close political race and I think every vote matters."
• Karla, 27, FIT student: "I'm not voting due to my legal status. I've been here for more than half of my life, and I have no rights."
• Harrison, 20, UCLA student: "I'll be voting red in this midterm election because the government has gotten to be a little bit too swollen and there's too much government spending and we need to cut it down."
• Patricio, 23, NYU student: "I'm voting because as a recently naturalized citizen I didn't have the opportunity to vote in the 2016 elections and I want to use my new voice for those that don't have one."
• Saaf, 20, Ohio State University student: "I am not voting because I did not feel represented in the last election."
• Rachel, 23, grant writer in New York: "I'm not voting in the midterm elections because I'm just busy."
• Cole, 21, George Washington University student: "I'm voting to keep Republicans in power because I want to show that young people are conservatives."
• Mamoun, 20, Ohio State University student: "I'm voting because we need to get Trump out of here."

Voting confusion in crucial Arizona county

The Arizona Senate race between Republican Martha McSally and Democrat Kyrsten Sinema is neck and neck, as a polling location in Maricopa County, Arizona, turned away dozens of voters Tuesday morning because they weren't in the right precinct.

But the location, inside the Tempe Historical Museum, was clearly advertised as an open "vote anywhere" site, CBS News correspondent Paula Reid reports. People were lined up before 5 a.m., and at least a dozen voters told CBS News they were turned away and didn't have time to go to another location before work.

Maricopa County is home to roughly two-thirds of Arizona voters, and has been fraught with voting issues over the last few cycles.

Pelosi says she's "100 percent" confident Democrats will take the House

House Minority Leader Nancy Pelosi said she is "100 percent" sure Democrats will take the House, speaking at a news conference with Democratic Rep. Ben Ray Lujan, chairman of the Democratic Congressional Campaign Committee.

"I'm confident we will win," she told reporters.

Pelosi emphasized that Democrats have created a compelling message by highlighting the GOP "tax scam" and efforts to gut the Affordable Care Act.

"When we win, on the opening day, our Democratic Congress will be transparent," Pelosi said.

As California goes, so goes the House?

Typically, national elections are decided long before ballots are counted in California, but this year is different, CBS News correspondent Carter Evans reports. Some are predicting the future of the House could be decided in Southern California.

CBS News is following seven races in the state where Republican seats might flip to Democrats, and four of them are in Orange County. The birthplace of Richard Nixon has long been considered a Republican stronghold in a largely Democratic state, but that is changing.

All four districts being contested on Election Day voted for Hillary Clinton in 2016 and are populated by a rapidly growing Latino and Asian immigrant demographic. Each of the races is within the polling margin of error, including the highest-profile battle between 30-year Republican incumbent Rep. Dana Rohrabacher, a staunch ally of President Trump, and Democratic businessman Harley Rouda, who has never held elective office in his life.

If the fate of the House comes down to California on Tuesday night, don't expect the results to be in right away. Because of the state's generous voting provisions and the popularity of mail-in ballots, it could be take days or even weeks before the races are called.

Border Patrol exercise in Beto O'Rourke's hometown postponed

A U.S. Border Patrol "crowd control" exercise originally planned for Election Day in El Paso, Texas, has been postponed, CBS News has confirmed. In addition to sitting right on the U.S.-Mexico border, El Paso is also the hometown of Democratic Rep. Beto O'Rourke, who is challenging Republican Sen. Ted Cruz.

Many Democrats called the exercise an attempt to suppress the Latino vote, CBS News correspondent Adriana Diaz reports from El Paso. Late Tuesday morning, the El Paso office for U.S. Customs and Border Protection, which oversees the Border Patrol, confirmed to CBS News that the exercise has been postponed.

Before the postponement was announced, a U.S. Customs and Border Protection spokesperson linked the exercise to the migrant caravan making its way to the U.S. through Mexico.

"We continually assess the capabilities of our facilities throughout the Southwest border and have been making -- and will continue to make -- necessary preparations," the statement said. "These include participating in operational readiness exercises and the mobilization of resources as needed to ensure the facilitation of lawful trade and travel."

Immigration is in the spotlight this Election Day. There is an estimated 1.4 million undocumented immigrants living in Texas.

According to a CBS News Battleground Tracker poll, 63 percent of Texans said illegal immigration is a "big problem." Cruz and O'Rourke are offering very different solutions.

Cruz said he wants a border wall and no amnesty granted to anyone who enters the U.S. illegally. O'Rourke wants a path to citizenship for undocumented immigrants and legal protections for asylum-seekers and so-called "Dreamers," who were brought to the U.S. illegally as children.

Both candidates appeared on CBS' "60 Minutes" on Sunday. Viewers can watch the segment in the player below.

Polls open in many states

Polls are now open in many states, including Virginia, Florida, Indiana, Pennsylvania and Georgia, where Democrat Stacey Abrams and Republican Brian Kemp are facing off in what could be a historic election. Abrams is vying to become the country's first black female governor.

When polls close across the country

Polls begin closing at 7 p.m. ET, and results will start coming in shortly after that. This animation shows the times when polls close in each state:

For an hour-by-hour breakdown of when polls close in key House races, check out this comprehensive guide by CBS News political correspondent Ed O'Keefe.

The current balance of power in the Senate

In the Senate, Republicans are hopeful they will retain their slim majority even if the party loses the House. Democrats need a net gain of two seats to win the upper chamber.

• Republican senators: 51
• Democrats: 49, including two independents who caucus with the party
• Total Senate races in play on Tuesday: 35
• Number of incumbent Democrats defending seats: 26, including two independents
• Number of incumbent Republicans defending seats: 6
• Number of open seats: 3

The current balance of power in the House

Republicans have controlled the House of Representatives since 2011, following the 2010 tea party wave that swept dozens of GOP members into office. Here's the partisan breakdown of the House as it stands now:

• Seats needed for a majority: 218
• Current Republican members: 235
• Current Democrats: 193
• Vacancies: 7 (5 former Republicans, 2 former Democrats)