TAMPA, Fla. – The Republican National Convention opens this week with President Obama and GOP challenger Mitt Romney running evenly, with voters more focused on Obama’s handling of the nation’s flagging economy than on some issues dominating the political debate in recent weeks.

A new Washington Post-ABC News poll shows Romney at 47 percent among registered voters and Obama at 46 percent — barely changed from the deadlocked contest in early July.

The findings continue a months-long pattern, with neither the incumbent nor the challenger able to sustain clear momentum, despite airing hundreds of millions of dollars’ worth of television ads — most of them negative — and exchanging some of the harshest early rhetoric seen in a modern presidential campaign.

Romney’s selection of Rep. Paul Ryan, R-Wis., as his running mate also did not fundamentally reshape the race, although the GOP’s conservative base has grown more enthusiastic about the ticket — but no more so about the chances of beating Obama in November.

Enthusiasm — or a lack thereof — will be on display as Republicans and Democrats hold their conventions over the next two weeks. The two parties will make their pitches to an electorate stuck in a deeply pessimistic mood. More than eight in 10 give the economy negative marks, and nearly seven in 10 see the country as seriously off track — an assessment that has not changed significantly all year.

The Post-ABC survey highlights the dominance of the economy as an issue in the 2012 election. Seventy-two percent of voters say the president’s handling of the economy will be a “major factor” in their vote this November.

Fewer voters place great significance on other issues that have roiled the race, including the GOP vice-presidential candidate’s plan to restructure Medicare, differences between the parties on women’s issues and Romney’s handling of his tax returns.

The proposed Medicare changes included in Ryan’s budget proposal in the House have been a focus of sharp debate since he was picked by Romney two weeks ago, and the specific changes to the health-care program are viewed negatively by about 2 to 1.

Though more focused on the economy, half of all voters still see Ryan’s plan as a big factor in their vote. That’s the same percentage that sees Democratic and Republican differences on women’s issues as playing a major factor.

Women’s issues dominated the campaign over the past week because of the controversy that erupted over comments by Missouri Rep. Todd Akin — a candidate for U.S. Senate — about “legitimate rape” and the ability of women to “shut down” their bodies in such circumstances.

Just 20 percent see Romney’s handling of his tax returns as very important to their vote.