President Obama's public approval rating has plunged to 50 percent as Americans increasingly doubt his ability to manage the nation's economy, according to a Washington Post-ABC News poll released on Wednesday.

Further, Obama's advantage in job approval over House Republicans, with whom he has had nearly constant and very public fiscal policy battles, has dropped from an 18-percentage point advantage in December, from 44 percent to 40 percent, giving the president only a relatively slight edge over his opponents in the House. 

"The poll contains ample evidence of the disillusionment voters feel toward both sides amid a sense of continuing dysfunction in Washington, which since December has been grappling with fiscal crises and deadlines of its own making," the Washington Post said.

The sequester, an automatic series of budget cuts to the federal government's discretionary spending plans that the President himself proposed, is not working to Obama's advantage. While a slim majority of poll respondents disapprove of the sequester, nearly 75 percent said it is having no impact on their lives, and fewer than half anticipate a toll on their family's finances if the spending cuts are continue.

Obama's 50 percent overall approval rating is "lower than that of most other modern second-term presidents at this point in their terms," the newspaper said, adding that since Harry S. Truman was president, only George W. Bush has been at such a low level at this point in his second term.

The president's approval among his core support groups is also falling: The percentage of liberals who place their faith in Obama instead of Republicans to handle the economy is 14 points lower than it was in December. Among women there has been a 12-point decline.

Political independents are also losing faith in Obama. Just two months ago, 54 percent of independents approved of the president's handling of the economy, and 41 percent disapproved. Now 50 percent of independents have a negative opinion of Obama's stewardship of the economy and only 44 percent approve.

Trust also is emerging as a challenge for the President. The poll indicates a closer divide among Americans on issues like immigration and gun control, "closer, perhaps, than the public's preferences would indicate," the newspaper said. Indeed, while respondents to the survey largely support White House initiatives on gun control, on the issue of "basic trust, the president and Republicans in Congress fare about evenly."