Democrats hold nearly three-quarters of the state's Congressional seats, a steady rise since they held about half two decades ago.
"Republicans have been on the ropes in California for years," says Dave Wasserman, who tracks elections for the non-partisan Cook Political Report.
Wasserman says the trend is exacerbated this year, because of Donald Trump.
"Trump could produce a bloodbath," says Wasserman. "Because California has a unique mix of demographic groups that are particularly hostile to Trump, including Latinos, Asian Americans and well-educated whites."
Wasserman says those groups could turn out in high numbers in Central Valley and Southern California races where Republican Congressmen Darrell Issa, Jeff Denham, and Steve Knight are running for re-election.
The Cook Political Report lists all three races as toss-ups. The GOP has held all of the areas they represent for more than a decade.
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