"The GOP trend is everywhere," says Steven Schier, a political scientist at Carleton College in Northfield, Minn., and author of several books on election trends. He notes that the states where Democrats are leading in Senate races cast 136 electoral votes in 2008, but the states where Republicans are leading cast 274 electoral votes.
Why isn't California joining the trend?
"Given that California leans strongly Democratic, a GOP national trend may have smaller effects statewide than [in] other states," says Mr. Schier.
Democrats are still popular among their base, even if that base is less unenthusiastic than it was a year ago, says Lara Brown, author of "Jockeying for the American Presidency: The Political Opportunism of Aspirants."
"California is one of the Democrats' base states," she says. "Hence it is not really a surprise that, as the election gets closer, California Democrats – including the many liberal Democrats that make up the state Democratic Party – are doing precisely what President Obama wants because they still approve and agree with him."