Boosted by improved public confidence in his economic stewardship, President Obama for the first time holds a clear edge over Republican presidential candidate Mitt Romney in a hypothetical general-election matchup, according to a new Washington Post-ABC News poll.

Romney, who notched his second consecutive victory Saturday by easily winning the Nevada caucuses, continues to solidify his position as the front-runner in the race for the GOP nomination. But as the contest has grown more negative, public impressions of the top Republican contenders have soured, as has the former Massachusetts governor’s standing as a general-election candidate.

Obama remains a polarizing figure, with Americans closely divided on whether he deserves reelection as well as on many aspects of his performance in office. Although better than they were a few months ago, his ratings on handling the economy and job creation remain negative, with intensity continuing to run against him.

The poll results underscore how important framing the contest could be to the outcome. If the fall campaign becomes largely a referendum on Obama’s tenure in office, as Republicans hope it will, he could struggle to win a second term — barring an economic recovery that vastly outperforms expectations. If, however, it becomes a choice between the incumbent and the challenger, as Obama advisers predict it will, the president’s prospects would be brighter.

The survey was conducted Wednesday through Saturday. During that time, the president and the Republican candidates were in the spotlight: Obama had just completed his State of the Union address and held campaign-style rallies in battleground states, and the Republicans were in the middle of a series of primaries and caucuses.

Overall, 55 percent of those who are closely following the campaign say they disapprove of what the GOP candidates have been saying. By better than 2 to 1, Americans say the more they learn about Romney, the less they like him. Even among Republicans, as many offer negative as positive assessments of him on this question. Judgments about former House speaker Newt Gingrich, who denounced Romney on Saturday night in Nevada, are about 3 to 1 negative.

Meanwhile, the president’s recent remarks are better reviewed. Among the roughly 6 in 10 Americans who heard or read about the president’s State of the Union address, 57 percent say they approve of most of what he laid out.

Obama’s overall approval rating stands at 50 percent, the highest in a Post-ABC News poll since a brief run above 50 percent immediately after Osama bin Laden was killed in early May. Still, nearly as many — 46 percent — disapprove. Among registered voters, 49 percent say Obama’s performance warrants a second term; exactly as many say it doesn’t.

Among political independents, who are likely to determine the outcome of the election, 47 percent approve and 50 percent disapprove of the way he is handling his job. The president’s approval rating among independents had dipped as low as 34 percent in the fall, and just a month ago, he faced a 10-point deficit here.

The 50 percent mark is widely considered a critical threshold for an incumbent seeking reelection, with a president’s chances greatly diminished at levels below that mark.

In a general-election test, Obama leads Romney 52 to 43 percent among all Americans; more narrowly, 51 to 45 percent, among registered voters. Among all adults, it’s Obama’s first time topping 50 percent in a head-to-head matchup with Romney since July; it’s his first time ever above that point among registered voters.

Obama’s momentum since mid-January has evened the score with Romney among political independents. Among independent voters in the last Post-ABC poll, Romney held a 12-point edge; now these voters split 48 percent for Obama, 47 percent for Romney.

The new survey also tested Obama against Gingrich. In that matchup, the president is ahead by 15 points overall and 11 among registered voters, both similar to the numbers from January.

The fault lines in the coming election, should Obama be pitted against Romney, are clear from the survey.

Romney has argued throughout his campaign that his business background gives him superior experience to turn around the economy and boost job creation. His pedigree is widely considered a positive and, among registered voters, he has a narrow edge over Obama on handling the economy in general. The former governor also leads on handling the federal deficit, an area where the president’s ratings remain stuck in solidly negative territory.

But when it comes to job creation — which has been the subject of fierce debate in the GOP contest — Romney and Obama are dead even in voters’ minds. They are also closely matched when it comes to handling taxes — another likely flash point in the coming campaign.

And in other areas, Obama has big leads, including on the question of who would better protect the middle class, handle foreign policy and fight terrorism.

Romney has been criticized as being out of touch with average Americans, a view that has been reinforced by several verbal gaffes he made on the campaign trail, including remarks about “the very poor” that were perceived as dismissive. At this point, the impression has stuck: Fifty-two percent of voters say Obama better understands the economic problems people are having, while 37 percent say Romney does.

The latest employment report, which showed 243,000 new jobs created in January and the unemployment rate ticking down to 8.3 percent, gave Obama a psychological boost, but he is far from out of the woods on the issue that continues to dominate the contest.

About nine in 10 people still rate the economy negatively, and among independents, 50 percent view this as a big strike against Obama’s reelection bid; far fewer, 33 percent, say it is a good reason to back his candidacy.

In contrast, by nearly 5 to 1, independents are more apt to view Romney’s business experience as a reason to support rather than oppose him.

However, his private-equity experience is a mixed blessing for him. The poll suggests that he has considerable work left to do to turn his business biography into a clear asset. One indicator: Thirty-three percent of all independents say Romney’s work in private business helped create jobs, 34 percent say it did more to eliminate jobs and 33 percent expressed no opinion.

Romney’s wealth also divides the public. Among all Americans, 43 percent see his fortune — estimated at $250 million — as a “positive” because it suggests that he has achieved the American dream. But just as many, 44 percent, consider his wealth a “negative” because it suggests that he benefited from opportunities that are not available to most people.

Romney is vulnerable on the issue of personal taxes. The former governor released his tax returns two weeks ago, showing that he paid an effective tax rate of about 14 percent. Two-thirds of all Americans say they do not think he is paying his fair share.

Romney has fought back, arguing that attacks on his or anyone’s financial success represent class warfare and criticism of the capitalist system that he said has made the United States the strongest and most innovative economy in the world. He has said repeatedly that Obama has a poor record on the economy because he doesn’t understand what makes the free-enterprise system tick.

Obama has sought to make economic fairness, particularly for the middle class, a centerpiece of his economic message. The poll underscores that Obama has remained on the high ground here. Fully 68 percent view the federal tax system as stacked in favor of the wealthy, not the middle class. More than seven in 10 support increasing the taxes of those earning more than $1 million a year — an idea the president has long pushed.

The poll was conducted by telephone Wednesday to Saturday among a random national sample of 1,000 adults. Results from the full survey have a margin of error of plus or minus four percentage points.

Polling manager Peyton M. Craighill and polling analyst Scott Clement contributed to this report.