According to the University of Virginia's Center for Politics, the race has gone from being a toss-up to leans Democratic. The rating is compiled by Larry J. Sabato's Crystal Ball.
In his comments on this and other California congressional races, Sabato says "If there is one state where Republican House chances appear to be slipping, it’s in heavily Democratic California, which is why we’ve added Reps. Dan Lungren (R, CA-7) and Jeff Denham (R, CA-10) to Rep. Brian Bilbray (R, CA-52) in the “leans Democratic” column, meaning we believe all three incumbents are underdogs in their battles to return to Congress. The television air war in all three districts has been fierce; these districts occupy three of the top six slots on the list of total spending by outside groups according to the Los Angeles Times. By this time next week, Rep. Mary Bono Mack (R, CA-36) might join them in the endangered column. Our ratings have Democrats gaining four net seats out of California along with four out of Illinois."