Poll watch: Obama leads Romney in four swing states

New polls in four battleground states show President Obama holding a lead of 5 to 7 points over Republican nominee Mitt Romney, reinforcing the national surveys that indicate that the incumbent gained ground with his convention last week.

Of the four, Obama’s largest lead comes in the critical state of Ohio, where he leads Romney 50% to 43% among likely voters, according to the latest NBC/Wall St. Journal/Marist University poll. The survey also polled likely voters in Florida, where Obama led 49% to 43%, and Virginia, where he led 49% to 44%.

In a separate survey by New Hampshire’s WMUR-TV, Obama led Romney 45% to 40% in that state.

Predict a winner: Updated battleground states map

The polls in all four states were taken in the days immediately following the Democratic nominating convention, so they may have caught Obama at a high point. Often – although not always – candidates gain ground after their conventions, then see their support erode in subsequent weeks.

Still, the results highlight the challenge that Romney faces. To gain the 270 electoral votes he needs for election, he would need to win most of the states that the two campaigns consider battlegrounds. Currently, Obama appears to have at least a small lead in all those states except for North Carolina, where recent polls have shown the two neck and neck.

The new swing-state polls show two reasons why Obama has maintained that lead: Voters continue to view him more favorably than Romney, and Romney has been unable to persuade swing-state voters that he would be better able to handle the economy.

The gap in favorability is particularly large in Ohio, where 51% of likely voters have a favorable impression of Obama while only 40% feel that way about Romney. In other states, Romney comes closer to parity with Obama, but only in Virginia does the Republican nominee get a net-favorable rating, 46% to 45%, compared with 53% to 43% for Obama.

Asked which candidate could best handle the economy, Ohio voters, again, have the most negative view of Romney. In that state, likely voters favor Obama on the economy by 48% to 44% for Romney.

The Obama campaign has spent the summer bombarding Ohio voters with advertisements criticizing Romney’s business and economic record. In particular, they have emphasized the president’s decision to bail out the U.S. automobile industry, which Romney opposed. The state has a large number of jobs tied to the car and truck business.

In national surveys, Romney used to enjoy majority support on the question of who could better handle the economy, but he’s lost that margin since the Democratic convention. Support on that question is key for his campaign since Obama gets much higher marks on other issues, including who could best handle foreign policy.

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