Analysis: The Final Countdown to Election Day Begins

VIDEO: Matthew Dowd, Nicolle Wallace and Donna Brazile discuss the campaigns on the eve of the
WATCH Election 2012: Both Romney, Obama Campaigns Believe They'll Win

In this razor-thin presidential race, everyone has a theory about where things will end up on Election Day -- with some even predicting control of the White House won't even be settled by the time we go to sleep Tuesday night.

The Obama campaign points to the president's lead over Mitt Romney in many of the key swing states as evidence that finding a way to the magic number -- 270 electoral votes -- based on the current map is still a tougher slog for the Republican challenger than for the incumbent.

But today, the last marathon day of the 2012 election cycle, indications about the tightness of the race are everywhere. In our own ABC News-Washington Post tracking poll out Sunday night the contest between the two presidential contenders remains deadlocked, with 49 percent support for Obama among likely voters compared to 48 percent for Romney.

"That brings it down to turnout (in an election in which 27 percent of likely voters say in fact they've already voted) and there Obama has a potential advantage," notes ABC News pollster Gary Langer. "He holds a 7-point lead over Romney in the share of his supporters who say they're very enthusiastic about their choice -- 69 percent of Obama's backers, 62 percent of Romney's."

And look at a state like Virginia where an NBC News-Wall Street Journal-Marist poll out this morning found Obama ahead by just 1 percentage point (within the margin of error), 48 percent to 47 percent over Romney.

Meanwhile, ABC's David Muir highlights a crystal ball column on by Republican strategist Alex Castellanos, in which he predicts a Romney win:

"Late polls in 1980 gave Ronald Reagan only a 2 percent to 3 percent lead over Jimmy Carter. Reagan ended up winning by nearly 10 percent. For the same reason, I would expect this campaign's final public opinion polls and exit polls this Tuesday to under-report the Republican vote by a handful of points."

And ABC's Jonathan Karl starts us off on Election Eve with a startling thought -- was this entire race much ado about nothing?

Karl notes that in an interview with MSNBC veteran political prognosticator Charlie Cook made the following prediction:

--Barack Obama will be re-elected President

--53 Democrats and 47 Republicans in the newly elected Senate

--240 Republicans and 195 Democrats in the House

Now consider that the current political breakdown is this:

--Barack Obama is the President

--53 Democrats and 47 Republicans in the Senate

--240 Republicans, 190 Democrats and 5 vacant seats in the House

In other words, Karl observes, after a multi-billion dollar campaign it is quite possible that nothing at all will have changed in the national political lineup. Nothing.