Clinton is a big draw with Democrats. He can pull in financial support and motivate the base. In a competitive East Bay congressional district, Rep. Jerry McNerney, D-Pleasanton, is hoping Clinton's appearance does just that.
Clinton came to support four Central Valley Democrats.
"The four people I'm on the stage with, two in Congress, two trying to get there, they each in their own way represent the American dream," Clinton said.
The two incumbents, McNerney and John Garamendi, D-Solano, represent the eastern edge of the Bay Area.
McNerney is considered the most politically vulnerable.
"Before he ran for Congress, he was in the wind turbine business supporting wind energy," Clinton said.
This time around McNerney is in a newly drawn district facing a well-funded Republican opponent.
Ricky Gill is running his own largely upbeat ads while outside supporters attack his Democratic opponent.
The U.S. Chamber Of Commerce out of Washington D.C. is spending millions attacking congressional Democrats in California. Their political director says the path to maintaining a pro-business majority in the House of Representatives goes though California.
Gill says the out-of-district support is only natural.
"Folks are going to see outside groups flock to races where there are competitive opportunities and the 9th district is one of them," Gill said.
McNerney has a 10-point advantage in registered voters in the 9th district.
"The Democratic Party is the party that stands up for the middle class," he said.
But ABC7 News political analyst Bruce Cain says this Central Valley race, and the others that brought Clinton to Davis, are exactly the kind of small to medium market races where the Citizens United decision on unlimited campaign contributions can have the biggest impact.
"You're more likely to be able to get buys and get notice in those smaller markets than you are in the big markets so I can see where the potential for money making a difference is very great in California," Cain said.
There's a lot of talk about the impact of Citizens United; Cain says the small and medium market races in California's Central Valley and across the country is where the money's going to make the biggest difference and have its biggest impact.