We are either going to know early this evening whether Republicans will take control of the U. S. Senate, or we are going to know very late. Either way, it looks like a long night ahead for Sarah Palin.

A Republican takeover of the House of Representatives is a foregone conclusion. The only suspense is in the magnitude of the GOP wave, and whether any big-name, veteran Democrats might be caught in the undertow.

The Senate gavel, however, is likely to stay in Democratic hands. Republicans would pretty much have to run the table, with victories in nearly every competitive race, to pick up the net gain of 10 seats they need to get a Senate majority. Such a sweep is not inconceivable – in fact, it happened on a smaller scale in 2006 when Democrats retook the majority – but it is a long shot.

Palin had a big hand in making it a long shot. She is already on the outs with large elements of the party leadership, and it will be interesting to see whether rank-and-file Republicans, who will select the GOP presidential nominee in 2012, become less enamored of her if she is blamed for the party falling one or two seats short of a Senate victory tonight.

To win the Senate, Republicans must defend seven seats their party already holds in New Hampshire, Florida, Ohio, Kentucky, Louisiana, Missouri and Palin’s home state of Alaska. They also have to win several Democratic seats where they are expected to have easy victories, including North Dakota, Arkansas and Indiana. All of this, except possibly for Alaska, appears well within the GOP’s reach.

Assuming the Republicans win all these races, they then need to pick up seven out of eight competitive races for Democrat-held seats. Those are in Pennsylvania, West Virginia, Wisconsin, Illinois, Colorado, Nevada, California and Washington.

Two of those races are in the Eastern time zone. If the Democrats win Pennsylvania and West Virginia, they will keep their Senate majority. It’s that simple.

Assuming Republicans win at least one of those Appalachian states, we can turn our attention to the Midwest races in Illinois and Wisconsin. A second Democratic victory there would clinch the Senate.

If a GOP winning streak makes it past the nation’s midsection, we will have a late night as we await results from Colorado in the Mountain time zone, and the Pacific races in Nevada, California and Washington. Recent polls have tended to favor Democrats in the latter two states, so it will take a late surge by the Republicans there, and a sweep nearly everywhere else, to flip the Senate.

It did not need to be so difficult for the GOP. The Delaware seat formerly held by Vice President Joe Biden seemed likely to go to Republican Rep. Mike Castle before a Palin-backed candidate, Christine O’Donnell, upset Castle in a primary. O’Donnell’s candidacy proved to be every bit the disaster that Republican insiders predicted. Democrats seem nearly certain to hold that seat.

An even bigger Republican train wreck looms in Alaska. A comatose Republican is usually able to beat any Democrat in statewide elections there. This time, however, there are two comatose Republicans in the race. Incumbent Lisa Murkowski was knocked out by Palin-backed insurgent Joe Miller in the primary, but is running as a write-in candidate. Miller, meanwhile, imploded in his attempts to sidestep questions over his use of government-owned computers for political purposes. The bedlam has created an opening for Sitka Mayor Scott McAdams, the Democratic nominee.

Palin has blamed the media for undermining Miller. The bottom line, however, is that a longstanding feud between Palin and Murkowski may be what comes between her party and Senate control. This is entirely in keeping with the style that has made Palin the Calamity Jane of Republican politics.

Palin unquestionably has a loyal following among many voters in the GOP’s conservative base. Her endorsement can help a candidate win a party primary, and it can help in a general election in a right-leaning House district, or even in some rural Southern states.

But Palin has little appeal to the independent voters who are otherwise breaking so well for the Republicans in today’s election. She also does not get along well with others, as her endless quarrels with everyone from John McCain’s presidential campaign staff to her daughter’s ex-beau amply demonstrate. These are not helpful traits for aspirants to national office.

Palin is apparently looking to parlay punditry and power-broking into a place atop the Republican ticket in 2012. It is a remarkable ambition for someone who was unknown to most of America before the summer of 2008, particularly someone who walked out in mid-term from the highest position she has ever held. Of course, we recently elected a president who was unknown to most of the country just four years earlier.

I suspect President Obama would single-handedly nominate Palin to be his next opponent if he could. In the end, that very notion might be enough to stop the GOP from choosing her, though I doubt it.

Still, it is one thing to go from anonymity to acclaim, as Obama did, and another to maintain that acclaim through four years in the public eye – as Obama is finding out.

Tonight may be the night Palin begins to learn the same lesson.

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