Primaries 2010: Endorsement Battles

WASHINGTON, Aug. 9, 2010 -- Tuesday elections across the country include a political-endorsement battle royale, with the current president on one side of the race in Colorado and former President Bill Clinton on the other.

And a bevy of Republicans thought to be eying their own presidential campaigns have settled on either side of the Georgia gubernatorial race.

2010 Election Maps: Follow the Senate, House and Governors' Races

Here's a whip around the country and a primer on what to watch for Tuesday night. Any story on endorsements should include a disclaimer that there is little evidence that they can sway a race.

In these cases, however, the divides are striking enough to mention.

Clinton vs. Obama

Nobody thought much of it back in late June when Clinton endorsed underdog Andrew Romanoff in Colorado. Michael Bennet, despite his never having run for office before, was appointed to the Senate seat there and he's the White House horse in the race.

More on the 2010 Races in Colorado

Bennet had the lead and Clinton would not be stumping in person Romanoff. But Romanoff is a fighter. He has sold himself as a Washington outsider and has pledged not to take money from political action committees.

He has gone negative on Bennet, tying him to Wall Street in ads and exploiting a New York Times expose about exotic and controversial loans taken out by the Denver Public School system when Bennet was superintendent.

There are indications that Bennet's lead is all but gone, according to public polls that showed the race tightening and private admissions from Democrats that what once appeared to be a sure win for Bennet has become too close to predict.

Clinton helped incumbent Blanche Lincoln in Arkansas. Will he help insurgent Romanoff topple the incumbent in Colorado? Read more about that here.

While he won't appear in person in Colorado, the former president recorded an automated message that will go out to some Colorado voters. Listen to it here. Obama praised Bennet in a tele-town hall Aug. 3.