In 2012, there are now three plausible scenarios that would each give Barack Obama and Mitt Romney 269 electoral votes in the November election. A candidate needs 270 votes to become president. (See the 2012 Electoral Map Forecast here.)
And there are two even more bizarre twists. If the Democrats retain control of the Senate in the general election and the presidential candidates are tied, Mitt Romney would likely become president and Joe Biden would be his vice president.
But if Barack Obama gets the most votes in Nebraska's second congressional district, which covers Omaha, he will get one electoral vote - which he did in 2008. The heavily Republican state is one of just two states (the other is Maine) that award electoral votes by congressional district, so winning Omaha means winning one of the state's five electoral votes.
Thanks to the 12th Amendment, a tie in the presidential race is sent to Congress once the electors from each state cast their votes in December. If a candidate doesn't have a majority of the electoral votes, the House picks the president and the Senate picks the vice president.
So in 2012, a tie is as good as a win for Mitt Romney, since the GOP controls the House. The Democrats currently control the Senate, and if they retain control after November, Biden would win a subsequent vice presidential vote in the runoff election.
The 12th Amendment sought to clean up the convoluted election of 1800, when Thomas Jefferson and Aaron Burr tied in the Electoral College, and tie-breaking vote by Congress resulted in an awkward pairing of rivals John Adams and Thomas Jefferson. The amendment was ratified in 1804, and its rules decided the 1824 election, when the House picked John Quincy Adams over Andrew Jackson when neither candidate had a majority.
But the passage of the 23rd Amendment changed the electoral math. When that amendment awarded three electoral votes to the District of Columbia in 1961, the total number of electoral votes became 538 - an even number that can be split exactly in half.
The three plausible tie scenarios
As we move through September, most political experts agree that nine states are toss-up elections that are too close to call. Two other states - Michigan and Pennsylvania - could come into play.
So quite simply, there are various combinations of those nine states' votes that come out to a 269-269 vote tie between Obama and Romney.
Politico has an app that lets you test your own combinations, in a sort of Electoral College Sudoku, to find the ties yourself.
But here are the mostly likely deadlock combinations.
Scenario 1: Romney takes Florida and Ohio, and four other swing states
If the GOP contender can take Florida and Ohio, the two biggest swing-state prizes, then all bets are off. Add North Carolina and Wisconsin, and then either Iowa or Nevada, and Romney has exactly 269 electoral votes.
North Carolina and Wisconsin (Paul Ryan's home state) are definitely possibilities for Romney. In current polling, Romney leads in North Carolina and Obama has small leads in Wisconsin and Iowa.
Scenario 2A and 2B: Romney takes Florida and Ohio, and five other swing states
This scenario also requires that Romney take Florida and Ohio, and then he has two possible combinations: Colorado, Iowa, Nevada, and Wisconsin; or North Carolina, New Hampshire, Nevada, and Iowa.
Both combinations give Romney 269 electoral votes. New Hampshire and Colorado seem like longer shots for Romney, but he remains in striking distances in those two states, according to recent polls.
Scenario 3: Romney loses Ohio but gains Michigan
Stranger things have happened in elections, but substituting Michigan for Ohio could be a big win for Romney. Then, the GOP needs to take Florida, Virginia, Wisconsin, New Hampshire, and Iowa or Nevada. The result: 269 electoral votes!
Scenario 4: Romney loses Ohio but gains Pennsylvania
It would be a long shot, but Pennsylvania is on the edge of being a swing state. Add Florida, Virginia, Wisconsin, and Nevada, or Iowa, and the results come to 269 electoral votes.
A lot of things need to go right for Romney to win Pennsylvania, including a low voter turnout in the Keystone State and a swell of grassroots support west of Philadelphia. This is definitely a longer shot than the three scenarios we mentioned above.
Scenario 5: Hey, don't forget about Omaha!
So what if President Obama takes just Iowa, Michigan, Wisconsin, and North Carolina? Then the total results become 270-268 for Romney. But then President Obama wins the one vote in Omaha, and it moves back to a tied election.
Want another combination? How about Florida, Ohio, Colorado, Virginia, and Wisconsin for Romney? That also gives Romney a total of 270 electoral votes, before that Omaha adjustment and the race becomes a tie.
Or try out this scenario: Obama takes Florida and Ohio, and loses every other swing state and Michigan. The result: Romney has 270 electoral votes, and an Omaha vote for Obama ties the election again!
The bottom line: Omaha is the deciding factor in our first three scenarios, which show a tied election if Romney can win Florida and Ohio, and the right combination of four or five of the remaining swing states.
Obama then breaks the tie if he takes that one electoral vote from Omaha, with its population of 570,000 people (which is about half the size of Palm Beach County in Florida).
Of course, Nebraska and Maine are the only two states that divide their electoral votes by congressional district, and that has only happened once since both states changed their laws.
That was in 2008, when candidate Barack Obama took Omaha from John McCain.
A local TV station in Omaha says local polling shows Romney with a 4 percent lead over Obama in the city, as both sides spend heavily.
A Democratic official told Fox 42 News both sides were aware of the significance of that one electoral vote.
"As a Democrat in Nebraska the second congressional district obviously had an advantage over the rest of the state and if we can use that advantage to help the president and get one more electoral vote that could be the difference between 269 and 270 votes," said Chris Carithers with the Douglas County Democrats.
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