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Mitt Romney eked out bragging rights in the latest ABC News/Washington Post tracking poll, claiming 49 percent support among likely voters vs. Barack Obama's 48 percent - Romney's first numerical edge, however slight, since before the party conventions.

Slight is the word: Taking it to two decimals (for illustration only - not to imply false precision), Romney has 48.51 percent support, Obama 48.44 percent - about as close as it can be. Still, with rounding, Romney's 1-point numerical edge is his first since an ABC/Post poll Aug. 25.

See PDF with full results and charts here.

Underscoring Obama's challenges two weeks before Election Day, his job approval rating now stands at 49 percent among likely voters, its lowest since late September (48 percent) and trouble for him to the extent that the election is a referendum on his performance. Among previous incumbents, George W. Bush dipped to 50 percent among likely voters - but not lower - in the fall of his successful re-election campaign.

Moreover, likely voters now divide by 50-45 percent, Romney-Obama, in whom they trust to do a better job handling the economy. The 5-point gap, while not statistically significant, is its widest, again, since Aug. 25.

Obama, however, retains pushback on the question of empathy, another significant independent predictor of vote preferences. He leads Romney by 7 points, 51-44 percent, in who better understands the economic problems people in this country are having.

ENTHUSIASM and INTEREST - Interviews for the latest ABC/Post daily tracking poll, produced for ABC by Langer Research Associates, were conducted Friday through Monday, almost entirely before the candidates' final debate Monday night. While debates rarely directly impact vote preferences, they can more subtly influence campaign dynamics, as with Romney's gains in some underlying measures, such as strong enthusiasm among his backers, after the first debate Oct. 3.

Today Romney and Obama are precisely matched on that measure: Sixty-two percent of each candidate's supporters say they're "very" enthusiastic about their choice. That's a change from the last two presidential elections, in which the eventual winners, Obama in 2008 and Bush in 2004, clearly led their opponents in strong enthusiasm at this point. It's one reason the race this year is so close.

In a telling comparison, Obama's strong enthusiasm is a scant 3 points lower than it was two weeks before Election Day in 2008, but Romney's is a broad 24 points higher than McCain's four years ago. Compared to 2004, strong enthusiasm for Obama and Romney is similar to Bush's (60 percent), and well ahead of John Kerry's (50 percent) at about this time in their contest.

Another measure, interest in the race, has risen steadily: On Sept. 9, just after the party conventions, 51 percent of likely voters said they were following the election very closely. That's now risen to 64 percent, precisely the same as at this point in 2008.

GROUPS - With his overall support matching his previous high in late August, Romney's at new numerical highs in some individual groups - among "very" conservative likely voters, with 92 percent support; among married men, with 64 percent; and among seniors, with 57 percent.

Obama, for his part, retains strength in core Democratic groups, including a new high among liberals, 90 percent; as well as 93 percent support from blacks and seven in 10 among Hispanics. At 62 percent, his support among young adults, under age 30, rivals Romney's among seniors; the question is the extent to which young voters turn out.

Finally, if enthusiasm is a far closer call now than in 2008, so are early voting intentions. In ABC/Post polling four years ago, Obama won likely voters who said they voted early by a wide 18 points. Today, by contrast, among the 33 percent who say they will vote early (or already have done so), the contest is essentially tied, 50-48 percent, Obama-Romney.

Obama's difficulties compared with 2008 appear in another way: Among people who say they supported him four years ago, 85 percent still are doing so, but 12 percent say they'll switch to the Republican. Among McCain voters, by contrast, Romney's retaining 96 percent support.

METHODOLOGY - This ABC News/Washington Post poll was conducted by telephone Oct. 19-22, 2012, among a random national sample of 1,382 likely voters, including landline and cell-phone-only respondents. Results have a margin of sampling error of 3 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 Abt-SRBI of New York, N.Y.

Partisan divisions in this survey, Democrats-Republicans-independents, are 34-29-32 percent among likely voters. Partisan divisions in the 2008 exit poll were 39-32-29 percent.