April 16, 2012 -- Mitt Romney has emerged from the Republican primary season with the weakest favorability rating on record for a presumptive presidential nominee in ABC News/Washington Post polls since 1984, trailing a resurgent Barack Obama in personal popularity by 21 percentage points.

Thirty-five percent of Americans see Romney favorably, while 47 percent have an unfavorable opinion of the former Massachusetts governor. He's the first likely nominee to be underwater -- seen more unfavorably than favorably -- in ABC/Post polls in eight presidential primary seasons over the past 28 years.

Romney's gender gap in vote preferences in an ABC/Post poll last week -- he trailed Obama by 19 percentage points among women -- is reflected in his new favorability scores as well. Just 27 percent of women see Romney favorably, compared with 44 percent of men -- his lowest rating to date among women, and highest among men, in a dozen ABC/Post polls since September.

Obama, by contrast, has no such gap between the sexes; he's seen favorably by 56 percent of Americans overall, including 58 percent of women and 53 percent of men, surpassing Romney in both groups.

Romney also has an enthusiasm gap: Just 12 percent see him "strongly" favorably, about half as many as see him strongly unfavorably. Intensity of sentiment on Obama is more even, tipping slightly to the positive -- 30 percent strongly favorable, 26 percent strongly unfavorable.

It's worth noting that favorability is not the same as voting preference -- i.e., poll questions asking people whom they'd support if the election were today. That construct is a hypothetical one; the election is not today. Ultimate voting decisions are based on a range of factors – partisanship, policy preferences, perceptions of the candidates on policy and personal qualities alike. Personal favorability is one of the most basic measures among these.

This poll, produced for ABC by Langer Research Associates, supports an exclusive interview of Mitt and Ann Romney by Diane Sawyer, airing tonight on ABC's World News with Diane Sawyer and Nightline programs.

THE LONG VIEW – Romney's ratings are a bit better among registered voters, 40-48 percent favorable-unfavorable, though they still trail Obama's in this group, 54-43 percent. Nonetheless it's been a long rut for Romney; his favorability rating among all adults has steadily remained between 31 and 39 percent since fall, never yet cracking 40 percent. Its average across this time is 35 percent, exactly where it is today.

Still, Romney can point to previous turnarounds. His favorable score is just a whisker from the previous low, Bill Clinton's 37 percent in March 1992, in a race Clinton went on to win. But Clinton was damaged at the time by the Gennifer Flowers scandal and aided by soft ratings of the first President Bush, who was seen unfavorably by 47 percent, matching Romney's negative rating among all adults today.

Obama's not currently showing that kind of vulnerability: His overall 56 percent favorability rating is his most positive in nearly two years; 40 percent rate him unfavorably. Obama's favorable score has gained 9 points since September, and his unfavorable rating has dropped by 6, as economic gains lifted consumer sentiment out of its longest, deepest downturn in decades.

If Romney can improve, Obama can stumble. His favorability rating was nearly matched by John Kerry's at about this point in 2004 and Mike Dukakis' in 1988 -- yet both faded and went on to lose. On the other hand, Obama's rating now also was approximately matched by two incumbents who went on to win re-election, Ronald Reagan in 1984 and Clinton in 1996.

One bit of Romney's baggage is the public's negative assessment of the nominating process from which he's emerging. Thirty-two percent of Americans rate "the Republican primaries" as a whole favorably; 56 percent, unfavorably.

GROUPS – Romney's difficulties extend beyond his gender and enthusiasm gaps. Among independents, the usual swing voters in presidential elections, he's underwater by 34-47 percent, favorable-unfavorable. And perhaps reflecting the hard-fought Republican campaign, a fairly tepid 69 percent of Republicans see him favorably – up, however, by 11 points since mid-March.

These compare to a 53-42 percent positive rating for Obama among independents, and an 86 percent favorable score in his own party, 17 points better than Romney's in his.

Similarly, Romney's rated favorably by just 30 percent of moderates, vs. Obama's 63 percent in this group. And Romney's 57 percent positive rating among conservatives compares with Obama's 77 percent among liberals.

There also are broad gaps among racial, income and age groups, and by marital status:

Favorable ratings of Obama and Romney are about the same among whites -- 43 and 42 percent, respectively -- while Obama's unfavorable score is 9 points higher than Romney's in this group. The turnaround occurs among nonwhites, who rate Obama favorably by a vast 82-15 percent, compared with Romney's 21-54 percent. A quarter of nonwhites have yet to form an opinion of Romney either way.

Obama has a 29-point advantage in favorability over Romney among Americans with household incomes less than $50,000 a year; this shrinks to a 7-point difference among those with $50,000-plus incomes.

Favorable views of Obama are 36 points higher than Romney's among adults younger than 40; that eases to a 17-point gap among the middle aged and an essentially even 2-point split (in Romney's direction) among seniors.

Obama's favorable score is 9 points higher than Romney's among married adults – but this swells to a 37-point advantage among those who are not married. Romney and Obama are seen favorably by about equal numbers of married men, and Obama's unfavorable score is higher in this group. But he jumps to a 20-point higher favorable rating than Romney among married women, 25 points among unmarried men, and 45 points among unmarried women.

There's an education difference as well, specifically among whites. Romney's favorability rating is about the same among whites regardless of whether they have finished college or not -- 43 and 41 percent, respectively. Obama's is similar among non-college whites, 38 percent. But among whites with a college degree, Obama advances to 52 percent favorability.

While Romney's ratings have been largely stable since fall, Obama's, as noted, have improved, especially among some specific groups. Since hitting his presidential career-low 47 percent in September, his favorability rating has gained 17 points among under-30s and singles alike, 16 points among moderates, 15 points among Hispanics and 11 points among independents. He's also gained 8 points among Democrats, while his rating among Republicans hasn't changed.

In addition to the economy, Obama's benefitted from a greater personal connection with most Americans on a range of measures. In last week's ABC/Post poll he led Romney by 38 points in being seen as more friendly and likeable, by 26 points as more inspiring and by 12 points as better understanding the economic problems most Americans are having.

These views have arisen in the midst of two dynamics -- one, the contentious Republican primaries, the other, improving public ratings of economic conditions. The former are all but over, a change that should be welcome for Romney. The latter remains to be seen -- with the economy's direction as critical in the six months ahead as it's been in the six just past.

ABC News polls can be found at ABCNEWS.com at http://abcnews.com/pollingunit.

Read the PDF of the full analysis here.