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Barack Obama crossed into majority favorability among registered voters for the first time since spring in a new ABC News/Washington Post poll, further evidence of a convention boost. Mitt Romney trails in popularity, albeit with a number near his own high.

The shifts in this survey poll re-open the popularity gap between Obama and Romney - now 8 points in Obama's favor, 52 percent vs. Romney's 44 percent, after closing to 4 points last week (within the margin of error), after the GOP convention and before the Democrats had their say.

See PDF with full results, charts and tables here.

Obama's favorable vs. unfavorable ratings, 52-45 percent, are back in the positive zone, +7 percentage points, after dipping below the waterline last week, 47-49 percent. Romney, at 44-49 percent, remains underwater, for the 12 th time out of 14 ABC/Post favorability polls this year.

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Consistent with a larger ABC/Post political poll released yesterday, Obama has improved in his own party, with his with his popularity among Democrats matching his high for this election, 89 percent. He's at a new high among lower- and lower-middle income adults, and has moved back to positive ratings among women, 53-44 percent, after dipping negative among women, a first for Obama, immediately following the Republican convention.

Obama's rating among independent registered voters, by contrast, is essentially flat - 46-49 percent favorable-unfavorable this week, 45-51 percent last week. Nor did he see any change among political moderates in this poll, produced for ABC by Langer Research Associates.

Romney's rating is essentially unchanged from last week's 43-48 percent, although with some notable results among subgroups - his best favorability scores since May among moderates (albeit just 40 percent) and independents (44 percent), and his best to date among "very" conservative registered voters, 81 percent favorable.

HISTORY - While neither Romney (in particular) nor Obama are in a strong position in terms of personal popularity, others have done worse in previous post-convention polling - a comparative improvement especially for Romney, whose favorability ratings before the convention were the lowest for any presumptive nominee in pre-convention ABC/Post polls dating to 1984.

In previous post-convention polling, two candidates have received at least numerically lower favorability ratings than Obama's and Romney's now - John Kerry in 2004 and Mike Dukakis in 1988. Several others were either numerically lower than Obama now, or in a similar position.

METHODOLOGY - This ABC News/Washington Post poll was conducted by landline and cell phone Sept. 5-9, 2012, among a random national sample of 837 registered voters. Results have a margin of sampling error of 4 points, including design effect. The survey was produced for ABC News by Langer Research Associates of New York, N.Y., with sampling, data collection and tabulation by SSRS/Social Science Research Solutions of Media, Pa.