Three ways Election Day could get ugly

There isn't any polling to back it up, but trust us on this one: After roughly two years of campaigning, a deluge of campaign ads, and enough media coverage of President Obama and Mitt Romney to make a four-year-old cry, most Americans would really like the presidential election to come to an end on November 6.

But while it's likely that we'll know who has won the White House on Election Day - or, at least, by the early hours of the following day - it's far from certain. Below, we discuss three Election Day possibilities that could either keep the battle going beyond next Tuesday or prompt a national conversation about what some call a broken system.

An Electoral Vote Split

There are 538 electoral votes available to the candidates in the Electoral College. Why 538? It has to do with the fact that states are allotted electoral votes based on how many members they send to Congress. Every state starts with two electoral votes for their two senators, and then gets an electoral vote for each member it sends to the House. Add up the 100 senators and 435 representatives, and you get 535 electoral votes. Add in the three votes allocated to the District of Columbia, which does not have voting representation in Congress, and you're at 538.

One problem with that number, from an electoral perspective, is that it's even - which means that it's possible that a presidential election could yield an electoral vote tie. There are a number of ways the candidates could end up with 269 electoral votes each. (You can play with the iterations here, and see some other possibilities here.) The most likely scenario involves Mr. Obama winning the battleground states of Ohio, Wisconsin and New Hampshire as well as the states he is expected to win, while Romney takes the remaining battlegrounds (Colorado, Florida, Iowa, Nevada, North Carolina and Virginia) and the states he is expected to win.  

So what happens if there's a tie? Under the Twelfth Amendment, the newly-elected House of Representatives decides the president, with each state's delegation getting to cast one vote. Republicans are now the majority in 33 delegations, the Washington Post reports, while Democrats are the majority in 16. Republicans are widely expected to maintain control of the House, which means they are also likely to maintain their edge in terms of how many state delegations they control. And that suggests that a tie is likely to result in Romney being declared president. (Though if Mr. Obama wins the popular vote while splitting the Electoral College, members of the House will face pressure to follow the will of the people.)

The vice president, meanwhile, would be decided by the Senate - which Democrats are expected to maintain narrowly after Election Day. That raises the possibility of Romney taking the presidency but seeing the vice presidential slot go not to his running mate, Paul Ryan, but instead to the man who currently holds that office: Joe Biden.

A split between the electoral and popular vote

While national polls show the presidential race roughly even, state polls show Mr. Obama with a small edge in a number of battlegrounds. That raises the possibility of the following scenario: Mr. Obama takes more than 270 electoral votes thanks to narrow victories in a majority of the battleground states while Romney takes more votes overall, thanks in part to overwhelming victories in the deeply red states in the South. That would result in Mr. Obama winning reelection despite coming in second place in the national vote. When you consider that Mr. Obama is expected to win the big blue states by smaller margins than he did in 2008, such a scenario seems even less farfetched. (A situation in which Romney wins the Electoral College while losing the popular vote is also possible, though it's far less likely.)

Such an outcome would prompt some Republican outcry, but it probably won't be too loud: In 2000, after all, George W. Bush won the presidency despite losing the popular vote to Al Gore. What it would also potentially do is kick start a national conversation about whether it's time to effectively ditch the Electoral College. Due in part to frustration that only a handful of states get much attention from presidential candidates, there has been a push to make sure whoever wins the most votes wins the presidency; under a proposal known as the National Popular Vote bill, the states would agree to allocate their electoral votes to the candidate who wins the national popular vote. Though nine states (including the electoral behemoth that is California) have agreed to the plan, not enough have done so for it to take effect. If the presidency once again goes to the person who came in second place, however - for the second time in the past four elections - the movement could pick up steam.  

An effective tie in a key state

Picture this: With the vote settled in 49 states and the District of Columbia, neither candidate has the 270 electoral votes they need to take the presidency. In the remaining state - we're going to use Ohio in this example, since it's generally considered to be the most crucial battleground in the race - the vote margin is razor-thin. And suddenly the nation is plunged into a sequel to the battle that took place in Florida after the 2000 election, when lawyers poured into the state to battle for every vote and the election ultimately had to be decided by the Supreme Court.

The margin wouldn't really even need to be razor-thin. Professor Ned Foley of the Moritz College of Law at Ohio State told CBS News that if the candidates are within 10,000 votes of each other in Ohio on Election Day, "we'll be in overtime." (Foley's in-depth analysis of how it would all play out is here.)

The primary focus if the election is close will be on provisional ballots, which voters cast when a voters' eligibility is in question. There were about 150,000 of them in Ohio in 2004, and about 200,000 four years ago. In the 2004 race, Democrat John Kerry was down by about 136,000 votes in Ohio on election night. He conceded the following day because there weren't quite enough outstanding provisional ballots to suggest he could close the gap. But if the candidates are within 10,000 votes of each other in Ohio on Tuesday night - even if they're within 50,000 - don't expect a concession.

Here's how the process would go down: During Ohio's 10-day "verification" phase after Election Day, people who cast provisional ballots can go to their local election board to provide additional information to get their vote counted - the correct form of identification, perhaps, or proof of address. This is also the period when an estimated 20,000 absentee ballots that arrived after Election Day will be counted. (The other absentee ballots will already have been factored in.)

After that, election officials and lawyers from both sides will examine the provisional ballots and argue over if they should be counted. This is where the courts are most likely to come in. "Ohio has a history of litigating over the rules for county provisional ballots," said Foley.

Ohio voters will be using touch screen voting machines with paper trails as well as optical scans, so there won't be any discussion of Florida-style "butterfly ballots." But there is already controversy: UC Irvine Election Law expert Rick Hasen, author of "The Voting Wars," notes there has already been litigation over ballots counted in the wrong precinct, which he said could end ultimately up at the Supreme Court. (There are two cases: One involves whether votes should be counted when a voter shows up at the right location but has to cast a provisional ballot because a poll worker sent him or her to the wrong table, leaving them to vote in the wrong precinct. The other involves whether votes should be counted when a voter casts a provisional ballot from the wrong voting location altogether.)

It's also possible that unexpected issues will arise. Ohio's Republican secretary of state, Jon Husted, has already faced charges from voting rights advocates that he is seeking to tilt the playing field in his party's favor. Due to a glitch in processing change-of-address records, meanwhile, some of the state's absentee ballot requests may have accidentally been rejected. Further complicating matters is a new rule mandating that if you requested an absentee ballot but show up to a polling place, you have to cast a provisional ballot to ensure you don't vote twice.

After the verification process ends on November 16, there is another 10 day window for the official canvass of returns. (This is when the lawyers will fight over the provisional ballots.)  After that, election results are supposed to be certified. But if the candidates are within 0.25 percent of each other at that point, it triggers an automatic recount. And legal challenges could push any of the deadlines back, meaning the recount might not begin until December.

In theory, the recount would have to wrap up by Tuesday, December 11 - the "safe harbor" deadline by which Congress is required to honor a state's results. If Ohio were to miss that deadline, it might be able to make a decision by December 17, when the Electoral College is supposed to meet.

In addition to the legal battles over provisional ballots, there could also be controversy and litigation tied to real or imagined voter fraud. One Tea Party-linked group, True The Vote, plans to monitor elections for fraud - a process that critics contend could amount to voter intimidation or cause long lines at the polls. Republicans, meanwhile, say voting machines in Ohio and elsewhere are changing votes for Romney into votes for the president. And there are a whole host of unanticipated developments that could prompt partisans on both sides to cry foul. In other words, if Ohio is decisive and the race is close, we could well be in for a long and contentious slog.

"It'll look a lot like Florida in 2000, except now it'll also be fought out in social media, which it wasn't before," said Hasen. "You can imagine every decision being made about provisional ballots being the subject of partisan tweets."