Barbara Boxer takes out the knives:

Republican challenger Carly Fiorina's ads are as brutal. Silver gives Boxer a 78% chance at keeping the seat. His prediction on the Senate more generally:

Over all, the Senate picture is more fluid than a week ago, and somewhat better for Republicans. But were the election held today, they would probably not win the contests in California and Washington, and that would prevent them from accumulating enough seats to take over the Senate (even if they were to win other close races like Illinois, Nevada and West Virginia). Thus, Republicans probably need some additional momentum to claim the Senate, whether in individual states like California or nationally.

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