The latest poll out of California’s Senate race may not look as good as Republicans would like, but it’s not good news for Barbara Boxer and the Democrats, either.  Rasmussen’s latest survey of likely voters shows Boxer ahead of Carly Fiorina by five points, slightly down from a previous seven-point lead.  More importantly, the incumbent’s support declined into the mid-40s, suggesting a diminishing chance of winning re-election in an anti-incumbent environment:

The latest Rasmussen Reports statewide telephone survey of Likely Voters shows Boxer picking up 45% support, while Fiorina earns 40% of the vote. Five percent (5%) prefer a different candidate, and 10% are undecided.

Less than a month ago, the longtime senator held a 49% to 42% lead over her opponent, representing her best showing so far. Since February, Boxer’s support has ranged from 42% to 49%. In those same surveys, Fiorina, former CEO of Hewlett-Packard, has captured 38% to 43% of the vote. …

Most voters in the state see the contest as an ideological clash. Sixty-one percent (61%) view Boxer as a liberal politically, while just as many (63%) regard Fiorina as a conservative. This includes 36% who say Boxer is Very Liberal and 31% who view Fiorina as Very Conservative.

Forty-two percent (42%) of California voters think Boxer’s views are mainstream, but 41% see them as extreme.

Similarly, 40% label Fiorina’s views as mainstream, but just 32% believe they are extreme.

Boxer has a few things going for her in the internals.  She barely edges Fiorina among independents, for instance, 34/33, but with 23% on the fence, that could change rapidly down the stretch.  Boxer handily wins the youngest voter demo, which will probably not turn out in force in this election anyway, but she also wins the 40’s and 50-64 demos, too.  The two candidate have almost identical favorable ratings, with Fiorina having a higher percentage unsure and potentially winnable.

California is also still one of the states where Obama’s affiliation can help.  The President gets a 56% approval rating in the Golden State, far above his national rating in the latest USA Today/Gallup poll of 41%.  The approval rating of the Republican governor, Arnold Schwarzenegger, has cratered to 29%.  Fiorina is obviously not running as a Schwarzenegger Republican, but the brand itself may be a problem.

Or maybe not.  If Boxer’s support keeps hovering in the 45% range, it shows that she herself may be a big problem.  The more Fiorina focuses on Boxer’s extremism, recognized by 41% of all voters and 38% of independents, the closer she gets to pulling off the upset.