Tie Vote? Obama-McCain Electoral Tie Scenario

WASHINGTON, July 17, 2008 — -- Predicting the outcome of a presidential election is dangerous sport, but some political junkies are playing the game, running the numbers and coming up with a November surprise: a possible tie between Sens. Barack Obama and John McCain.

While it's highly unlikely, it is a mathematical possibility.

"Given how close it's been in the last couple years, there are some reasonable scenarios that you could get to a tie," said John Fortier, a political scholar at the American Enterprise Institute and author of "After the People Vote: A Guide to the Electoral College." "It's not the most likely scenario, but the states can add up that way where you have nobody getting to 270."

Under the sometimes wild and woolly American system of democracy, a presidential candidate must achieve at least 270 votes in the 538-member electoral college to win the White House.

If, for example, Obama wins all the states Sen. John Kerry, D-Mass., won in 2004, and picks up Iowa, Nevada and New Mexico, McCain and Obama would each win 269 electoral college votes -- locking the presidential election in a tie.

Election Night Scenarios: Run Your Own Numbers by Clicking Here on the ABC News Electoral Vote Calculator.

"It is implausible, but given what has happened in the last two elections you cannot thoroughly dismiss the implausible," said Jennifer Duffy, who analyzes Senate races for the nonpartisan Cook Political Report.

Under the 12th Amendment of the U.S. Constitution, if one candidate does not get 270 votes, the decision gets kicked to the House of Representatives, where each state gets a vote -- a formula that would likely guarantee an Obama victory.

"Each state delegation would have one vote and whoever won a plurality of that state's delegation would get that state's vote," said Stephen Wayne, a presidential scholar at Georgetown University.

That could get tricky, especially in states where Republican and Democratic members split the state evenly.