Independent voters have turned against Carly Fiorina over the last two months and the result is Barbara Boxer expanding her lead to 49-40 in the California Senate race after holding just a 45-42 advantage in a PPP poll two months ago.
Fiorina wasn't particularly well liked before the primary when 22% of voters said they had a favorable opinion of her and 30% said they viewed her unfavorably. Now they like her even less. Just 28% of Californians have a positive opinion of her, while 40% see her negatively. That shift has been particularly sharp with independent voters. Her favorability with them has risen from 15% to 20% over the last couple months, but her unfavorability has gone up much more rapidly from 23% to 40%.
As independents have grown to hold a more unfavorable opinion of Fiorina their loyalties in the race have shifted toward Boxer. The incumbent has a 48-38 lead with them now, flipping the 10 point deficit she faced to Fiorina at 42-32 back in May. Beyond that both candidates have pretty solid holds on their party's support- Boxer is up 77-13 with Democrats and Fiorina is up 77-13 with Republicans. To win in a heavily Democratic state like California Fiorina would need to get more crossover support from Democrats than Boxer did from Republicans and also win with independents. Right now neither of those things are happening.
Boxer's probably not completely out of the woods- her numbers still leave something to be desired with more voters disapproving (46%) of her than approve (44%). Even though they're planning to vote for her independents still don't actually like her, with 48% disapproving and only 40% approving. But it appears as though the more independents get to know Fiorina the more of them consider Boxer to be the lesser of two evils.
The trend in Boxer's reelection bids has been for her to look vulnerable early in the cycle and then get safer and safer as the election nears and her Republican opponent turns out not to make that strong of a candidate. We could be seeing that play itself out again this year.
Full results here