Mitt Romney trails Barack Obama by 19 points in basic popularity as the 2012 presidential contest inches closer to the main event, with a record 50 percent of Americans in the latest ABC News/Washington Post poll now rating Romney unfavorably overall.

Thirty-four percent hold a favorable opinion of Romney, the lowest for any leading presidential candidate in ABC/Post polls in primary seasons since 1984. His unfavorable score is higher than Obama ever has received; it's been exceeded by just one other Republican candidate this year, Newt Gingrich, and by only one top candidate in 28 years, Hillary Clinton in 2008.

Obama, for his part, remains above water - 53 percent favorable, 43 percent unfavorable in this poll, produced for ABC by Langer Research Associates. It's Obama's third consecutive month with a rating more than 50 percent positive, after dipping to 47 percent in September, the lowest of his presidency.

Romney's got three challenges: comparatively weak support in core Republican groups, lower popularity than Obama's in the political center and more Americans - about one in six - who have yet to form an opinion of him one way or the other.

Still, Romney may find better days ahead. The relatively high undecided group offers opportunity, should he prove able to win them over. And core Republicans may warm to him once the bruising GOP primary comes to a close, assuming he ultimately prevails.

CORE GROUPS - Although higher unfavorable ratings among independents, Democrats and liberals pushed Romney to a 50 percent overall negative rating this week, his more pressing problem, with the primaries still on, is his relative lack of popularity among core GOP groups.

Romney's seen favorably by 62 percent of Republicans and 47 percent of conservatives overall, including 54 percent of strong conservatives. Obama fares much better on the other side of the political spectrum - 86 percent favorable among Democrats, 75 percent among liberals.

The president peaks at 91 percent favorability among liberal Democrats, vs. Romney's 66 percent among conservative Republicans. These are like-sized groups: Liberal Democrats account for 16 percent of all adults in this poll, conservative Republicans for 18 percent.

Intensity of sentiment is an even sharper point of differentiation. Sixty-one percent of Democrats and half of liberals see Obama "strongly" favorably, the most in nearly a year. Strongly favorable ratings of Romney dive to 15 and 13 percent among Republicans and conservatives.

THE CENTER - Obama also leads Romney in favorable ratings among independents and political moderates. The former, in particular, customarily is a decisive swing-voting group in presidential elections. Half of independents see Obama favorably, 15 points ahead of Romney.

Romney's negative rating among independents, at 52 percent, is a new high for him in this group. Obama though, is not far behind, seen unfavorably by 46 percent of independents. And 12 percent of independents are undecided about Romney, vs. 4 percent on Obama.

Obama's rating among moderates is more broadly positive, 61-34 percent favorable-unfavorable. Romney, by contrast, has a net negative score among moderates - more see him unfavorably, 48 percent, than favorably, 35 percent, with 18 percent undecided.

OTHER GROUPS - Among other groups, Romney's rated favorably by 44 percent of Americans with incomes of $100,000 or more, 13 points better than his score among those with less-than middle incomes. Obama's favorable ratings exceed 50 percent across income groups.

There's also a bit of a gender gap for Romney, with favorable ratings of 38 percent among men vs. 30 percent among women. Obama's positive ratings again break 50 percent in both groups.

BACK IN TIME - Romney's favorability rating is lower than other leading candidates have received in ABC/Post polls during previous January-to-June nominating seasons. The previous low was Bill Clinton's 39 percent in March 1992.

On unfavorability, meanwhile, just one leading candidate has surpassed Romney's 50 percent, Hillary Clinton, at 54 percent in April 2008.

Obama, compared to previous incumbents, is ahead of George W. Bush's 47 percent in March 2004, and similar to Clinton's 56 percent in June 1996 and George H.W. Bush's 52 percent in March 1992.

The first President Bush's rating demonstrates that springtime favorability may not predict November outcomes. Nonetheless, Romney's tepid rating has been a persistent one; he's remained between 31 and 39 percent favorability in 11 ABC/Post polls this cycle, averaging 35 percent - essentially where he remains today.

METHODOLOGY - This ABC News/Washington Post poll was conducted by landline and cell phone March 21-25, 2012, among a random national sample of 1,016 adults. Results have a margin of sampling error of 3.5 points. 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.