What if one candidate wins the popular vote and the other wins the Electoral College? What if Republican George W. Bush and Democrat Al Gore tie in the Electoral College? How about if the Senate splits 50-50 between the two parties? Or if the House is essentially tied, with a slim majority for either party?

Or several of the above?

With the presidential election too close to call and control of Congress hard-fought to the end, political scientists and historians say their phones are ringing off the hook with all sorts of juicy what-ifs.

"It's wonderful. Between now and next Tuesday we can spin out endless possibilities," said political scientist Michael Malbin of the State University of New York at Albany. But he cautions, "There's something very real at stake here."

The American Enterprise Institute, a Washington think tank, got so many what-if questions that it scheduled a panel discussion Wednesday on the different possibilities.

"It's a useful exercise, since there is so much talk this year," said Walter Berns, a scholar who edited the group's guide to the Electoral College.

With the presidential race so close, it's conceivable that one candidate could win the popular vote while the other tops the Electoral College count. In that case, the presidency goes to the winner of the electoral vote.

The winner of the popular vote has lost the election three times, most recently in 1888.

In an even less likely scenario, the 538 members of the Electoral College could split 269-269. That's never happened.

But Michael White, the federal official responsible for coordinating the Electoral College, said he plugged some hypothetical state-by-state results into a calculator and was surprised to find "it wasn't all that hard to conjure a tie" for Bush and Gore.

He managed to do it without going through contortions such as awarding a safe state for one candidate to the other candidate.

A tie in the Electoral College would toss matters to the new Congress, its own makeup a question mark in the leadup to Election Day.

That's where the parlor game really takes some twists.

With an electoral tie, the presidential race would go to the House, where each state would have one vote and, at least in theory, there could be another deadlock. While the presidential question was being sorted out, the Senate would be called on to select the new vice president. And the Senate, where each member would have one vote, also theoretically could end up tied.

If no new president or vice president had been selected by Inauguration Day, the Presidential Succession Act would kick in, with the speaker of the House in line to serve as acting president, followed by the president pro tempore of the new Senate -- who could be Strom Thurmond of South Carolina, who turns 98 in December.

"There is a law or a rule for every one of these things," Berns said. "All they have to do is follow the rules and we'll end up with a president."

There are all sorts of hypotheticals surrounding the vote for Congress, too.

In the House, for example, Democrats would outnumber Republicans by gaining seven seats Tuesday. But one Democratic congressman, James Traficant of Ohio, has promised to vote to re-elect Republican Speaker Dennis Hastert. So the Democrats really need to pick up eight seats to take control.

There are other scenarios for a House tug-of-war, too, including party-switching after the election.

"Each party considers a couple of people in the other party to be targets of opportunity," Malbin said. "If it gets to within two or three seats, then there will be a lot of very interesting discussions going on."

In the Senate, Democrats still hold out hope of erasing the Republicans' 54-46 margin of control. Again, Tuesday's results may not be the final word.

Gore's running mate, Sen. Joseph Lieberman of Connecticut, also is on the Senate ballot and expected to easily win re-election. So if Democrats win the White House, Lieberman would resign his Senate seat and Connecticut's GOP governor could name a Republican replacement.

So a 50-50 split on Election Day with a Democratic president could soon become a 51-49 edge for Republicans.

But if Election Day produced both an evenly divided Senate and a Republican president, the advantage would still be with the GOP. That's because the Republican vice president, Dick Cheney, would be able to vote in the Senate to break a tie.

All the what-ifs are enough to make head spins.

"While it has some of the quality of working your way through a tall maze -- Harry Potter-style with little monsters around each corner -- it's not just a game," Malbin said. "It's not just minutiae."