Here are the races, candidates, and districts to watch to get a jumpstart on your post-election analysis.

In both Michigan and Wisconsin, the GOP candidate is favored for governor. Democrats have to hope that the Michigan House stays in their party and that in Wisconsin they hold on to narrow majorities in the House or Senate.

The other reason to pay attention to governor's races is that many of them are in key presidential battleground states. Strategists believe that a candidate has an easier time in a state if he or she can take advantage of the organization of the top elected official there. Nine key battleground states totaling 121 electoral votes are up for grabs in 2010: the five above plus Nevada, Colorado, New Mexico, and Iowa.

How enthusiastic?
There was indeed a giant enthusiasm gap in this election: between the people who used that term repeatedly and the audience who grew sick of it quickly. Now we'll see just how much more fired up conservatives were than Democrats. The key figure to watch going into the election was the difference between registered voters and likely voters. In the last Gallup poll, Democrats were down among both: Republicans led among registered voters 48 percent to 44 percent and among likely voters by a whopping 15 points, 55 percent to 40 percent. It was, said Gallup, "a lead large enough to suggest that regardless of turnout, the Republicans will win more than the 40 seats needed to give them the majority in the U.S. House."

So the question of the evening Tuesday is not whether Democrats can match Republicans everywhere. They can't. The question is whether, when Democrats put on their full effort in specific places, they were able to build a wall against Republican advances. Specific toss-up districts to watch to see if all the effort paid off: Ohio's 1^st, Ohio's 15^th, Wisconsin's 7^th, Nevada's 3^rd, and New York's 1^st. 

Is Obama toxic?
A number of Democrats tried to keep their distance from President Obama this year.  Gubernatorial candidate Alex Sink didn't want him to come back to Florida. In West Virginia, Joe Manchin—the governor and a candidate for Senate—refused to endorse Obama's re-election. In Indiana's 2^nd District, Rep. Joe Donnelly ran an ad touting his conservative stance on immigration over pictures of Obama and Pelosi. "That may not be what the Washington crowd wants, but I don't work for them," Donnelly says. "I work for you." Rep. Gene Taylor in Mississippi's 4^th District said he didn't vote for Obama. (And all this is to say nothing of the Democratic voters who are distancing themselves from  Obama. A recent AP poll showed 47 percent want him to have a primary challenge.)

Other candidates under threat did embrace Obama. Rep. Tom Perriello of Virginia called for the firing of Obama's economic advisers earlier this year, but he welcomed the president's visit at the end of the campaign. Sen. Barbara Boxer appeared with Obama at a late rally in California and put him in her final ad. Incumbent Democratic Gov. Ted Strickland of Ohio campaigned with Obama several times, including just a few days before the election.

Which group of candidates—those who invited the president in, or those who kept their distance—fares better on Election Day is another theme worth watching.

Which "old bulls" will go down?
During the final pre-election excitement, when the projection for Republican gains appeared to grow by an order of magnitude every day, there was talk about 26-term veteran John Dingell being under threat of losing his seat. If the longest-serving member in House history loses, it will be a gargantuan night for the GOP. Most election prognosticators don't believe that will happen. But that doesn't mean there won't be losses among members who have been in the House for a long time. Places to look for possible career-enders: 18-term Rep. James Oberstar of Minnesota, 17-term Rep. Ike Skelton of Missouri, 14-term Rep. Rick Boucher of Virginia, 15-term Rep.  Barney Frank of Massachusetts, 14-term Rep. John Spratt of South Carolina, and 13-term Rep. Paul Kanjorski of Pennsylvania.

Someone is going to make history
No matter what happens tonight it will be historic. Here are some bits of history that are likely to be undone:

• In the House takeover years of 1994 by Republicans and 2006 by Democrats, no incumbent of either winning party lost.
• In Pennsylvania, the governor's office switches parties every eight years, which means Republican Tom Corbett should win. But in Pennsylvania an attorney general has never won the office of governor, which means the Democrat Dan Onorato should win.
• Since World War II, the House has changed parties six times and in every case the Senate has switched, too.
• Colleen Hanabusa in Hawaii can retake the 1^st Congressional District from six-month incumbent Charles Djou, a Republican who won it in a special election. But in the state's entire history, a federal office-holder has never been kicked out of office.