President Barack Obama and the man who wants his job, Republican Mitt Romney, are locked in a neck-and-neck battle for the White House, with the challenger one point ahead in a new poll out Monday.

As the two head into their parties' conventions, beginning this week with the Republicans, the state of the US economy remains the dominant election theme, more than the issues including abortion that have roiled the political debate in recent weeks.

A Washington Post/ABC News survey of registered voters found Romney has crept ahead of the incumbent, 47 percent to 46 percent, a figure barely changed from early July.

More than eight in 10 voters give the economy poor marks, according to the Post, while 50 percent say they trust Romney more to handle the economy, compared with 43 percent for Obama.

A majority of respondents say they don't believe either candidate has what it takes to turn the struggling economy around. A full 58 percent say they are "not confident" that the economy will improve if Obama wins a second term, while 52 percent expressed a similar lack of confidence in Romney.

Romney has made only slight gains in the weeks since he chose Paul Ryan, the powerful House Budget Committee chairman, as his running mate.

And while Ryan's plans to overhaul entitlement programs like Medicare, the government health care program for retirees, are viewed negatively by about two to one, according to the survey, a full two thirds of respondents said Romney's VP pick would make no difference in their vote, with the remainder evenly split on whether it makes them more or less likely to vote for Romney.

Obama's re-election campaign has battered Romney, a multimillionaire investor and former governor of Massachusetts, for his refusal to release more than two years of tax returns, but just 20 percent of respondents see Romney's handling of his taxes as a major issue.

Obama holds some longstanding advantages, including double-digit leads on social issues, women's issues and likability.

A majority of voters also said he would be a better guardian of the middle class, although most also said they see Obama as favoring a bigger government than Romney wants.

The poll has a margin of error of plus or minus four percentage points.

A separate agency published a survey Monday highlighting Obama's pronounced advantage in a key demographic: Hispanics.

Latino Decisions reported that Obama maintained a 65-26 percent advantage over Romney among Hispanic voters.

Peeling such voters away from Obama is vital for Romney if he is to win Florida, the largest battleground state of all in the November election.

The Republican convention begins in Tampa, Florida on Tuesday, after Tropical Storm Isaac delayed the event by a day.