Gingrich versus Gore in 2008. Gore? Gingrich? They are not even running! But the possibility is not nearly as flaky as it sounds.

This election cycle creates a significant chance – the first in modern memory – that both parties could string out their presidential nominations until their conventions next summer. And if it’s a convention free-for-all, delegates could as easily turn to alternatives as not.

The 2008 presidential election is the first in 80 years with no president or vice president running. It has seen the earliest start for top-tier candidates in history – most were running hard by January. It has a more compressed schedule than ever before: Nearly two-thirds of delegates will be selected between the Iowa caucuses Jan. 14 and the slew of state primaries Feb. 5.

Conventional wisdom says this front-loaded schedule will help a front-runner sew up a party nomination early. That may be right. One candidate could catch fire, win Iowa, Nevada and New Hampshire and develop unstoppable momentum. Or a candidate may secure an overwhelming financial advantage and dominate TV ads leading up to Super-Mega Tuesday on Feb. 5.

But it could go entirely in the other direction. Why? One reason is the large field of candidates. Many are well-financed, and others have traction from a popular issue or a big geographic or ethnic base. That makes it less likely that one candidate can win all the early caucuses and primaries.

If no dominant candidate emerges from Iowa, Nevada, New Hampshire et al, then the up-to 22 contests on Feb. 5 – with primaries and caucuses spread from California to Delaware – are more likely to accentuate the divisions than anoint a winner.

But it is changes to the parties’ delegate selection rules that could cause the major shake-up. In past decades, large states with winner-take-all primaries gave huge boosts to front-runners. But now, the Democrats have abandoned statewide winner-take-all primaries, and the Republicans have them in only a few cases. Many states, such as California, have gone to winner-take-all by congressional district, which makes it hard for one candidate to capture all the delegates.

So here is a highly plausible scenario for either party, or both: A handful of candidates trade victories in Iowa, New Hampshire, South Carolina and Florida heading to Super-Mega Tuesday. When the dust settles Feb. 6, three or four candidates each hold 10 percent to 20 percent of the delegates chosen. With only one-third of the delegates still up for grabs, no one gains the upper hand through April. All have an incentive to stick around to see what happens at the conventions.

For those who yearn for a revival of Gore Vidal’s “The Best Man,” in which the presidential candidate was chosen in a smoke-filled room at the convention, think again. The parties also have abolished the “unit rule” that made such power brokers possible. The unit rule required all the delegates of a state to vote as a bloc for the candidate chosen by a majority.

How long delegates are bound to specific candidates varies from state to state, but few are committed beyond the second ballot. In a multi-ballot contest, all bets are off. Sooner or later – mostly sooner – delegates would be on their own to decide how long to stick with their candidate – and whether to shift loyalties as directed. Delegates may split all over the lot when it comes to their second choice.

Anything could happen: days of inconclusive balloting; a deal between candidates to break the logjam; a spontaneous shift on the convention floor or even a move to draft a new figure who is unsullied by the long campaign. Thus, Newt Gingrich, the Republican most likely to electrify a convention with a red-meat conservative rallying cry. Or Al Gore, whose full-throated populism and call to fix the planet could excite Democrats.

From 1872 until 1952, contested conventions were the norm in the United States. Since the ’52 contest, not one convention has gone to a second ballot. This election may finally reverse that trend, with twists and unexpected outcomes, a political junkie’s delight. Whether that will produce better nominees and a better general election is another issue.