A new Washington Post-ABC News poll shows sharply higher negatives for Cain, with Republicans also souring on the surprise front-runner. Overall, 44 percent of Americans say they have unfavorable impressions of Cain, up from 27 percent in mid-October, before the first allegations against him.

Nor has Cain been immune among fellow Republicans: negative ratings among Republicans have more than doubled over this time period, now reaching 36 percent. Cain hasn't lost support in his base, but the large number previously undecided now seem to have shifted negative.

Should Cain be the GOP nominee, he would have to make up ground lost over the past month. In the new poll, independents now tilt negative on Cain, and the candidate’s unfavorable number among Democrats has jumped to nearly six in 10.

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