“HOW DO WE beat the bitch?â€Â A South Carolina voter asked Republican candidate John McCain at a campaign event earlier this month.

This is about the time of year that politicians crank up the mudslinging, just in time for the early caucuses and primaries. This year, they̢۪ve had it cranked up for some months already, and at least one South Carolina voter is joining in.

Who can blame the candidates? This is the probably the most volatile presidential nomination race since Herbert Hoover̢۪s 1928 nomination.

In case you haven̢۪t been keeping track at home, the Republicans have no clear leading candidates in terms of wide, national support, but Mitt Romney is so far the clear leader in Iowa, who has the first primary-like event of the year. Mike Huckabee is a closer and closer second in that state, perhaps due to Chuck Norris̢۪ endorsement.

That̢۪s no joke.

With a largely unpopular foreign war and poor public perception of the economy thrown in the mix, the eight-year reign of the Republicans in the White House faces a viable challenge, assuming the Democrats don̢۪t find some way to screw things up.

The Democrats have two-and-a-half solid candidates, all in a dead tie for the Iowa caucus. Though I̢۪m not impressed with 2004 leftover John Edwards, he earns his half-count as the media-designated third frontrunner.

As in any election, it̢۪s too early to call anything this early on, but there are a few other historical precedents that could play out again.

Precedent 2004: Hillary̢۪s lead, like that of then-frontrunner Howard Dean in 2004, is waning. Dean was unable to win the Iowa caucus, and his campaign fell away. Winning the Iowa caucus would cement her support and keep her momentum through the other early primaries to the party̢۪s national convention.

Obama has a number of similarities with Dean, himself: his support is said to be largely youthful, a demographic historically unlikely to caucus. Whether or not this is reflected in the pre-caucus polls is uncertain — most refer to “likely caucus-ersâ€Â — but it’s a three-way race and probably will be all the way until Jan. 3 hits.

Better news for the Republican candidates is that, despite the momentum and money the Democrats built up in 2004, the GOP still won handily. The trick for the Democrats will be to attract a candidate who draws widespread and bipartisan support from registered Republicans who are dismayed by the war.

Only one Republican candidate has come out staunchly anti-war: Ron Paul. Paul is far from attracting even the support of a Romney or Huckabee, much less that of Fred Thompson or Rudy Giuliani.

Precedents 1992, 1912, 1860: Republican frontrunners are, for the first time in recent memory, mixed on core conservative issues, the most cited example probably Giuliani̢۪s support of abortion rights.

There̢۪s always the possibility of a splinter party or independent candidate messing everything up.

A candidate who splits the vote spoils the election for himself and his in-party rival. In 1912, Theodore Roosevelt̢۪s progressive Bull Moose party ushered in two terms of Democratic candidate Woodrow Wilson because the popular Roosevelt split from the Republican party, who nominated instead the incumbent: William Taft.

It hasn’t always worked out so cheerily for the Democrats. Abraham Lincoln, the first Republican president —he could be the only third party president ever, depending how you look at it — won the 1860 election once Democrats John Breckinridge, John Bell and Stephen Douglas split their shared constituency three ways.

If a full ideological conservative — with hard-line views on abortion and gay marriage — enters the race all gusto-ed up, or if Ron Paul gains momentum as an independent, there’s a clear route to victory for a focused, bipartisan-aimed Democratic campaign.

Of course, if there̢۪s one thing 2004 taught us, it̢۪s that the Democrats have a preternatural capacity for failure when given a certain thing.

Precedent 1968: An anti-war Democrat wins a hard-fought primary battle, but only minutes after claiming victory, a Kennedy clan member goes and gets assassinated. The Democrats nominate, for whatever reason, a pro-war Democrat and just make things harder for themselves.

Under this precedent, Richard Nixon, a Republican, is elected. Good thing he̢۪s dead already.

Wild speculation aside, there̢۪s always the Precedent 1948.

We can be sure that the overeager media will jump out at and latch on to wild speculation of every sort, with neither forethought nor care.

Dewey defeats Truman, indeed.

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