Obama During 2012 State Of the Union Address
President Barack Obama during his 2012 State of the Union address Reuters

President Barack Obama is topping Mitt Romney in a poll of 12 swing states, aided by a boost of support from independent voters, a new poll shows.

In these purple states, the president leads Romney 48 to 44, while getting 50 percent of the vote over Rick Santorum, who would get 42 percent, according to a new poll from Purple Strategies, which tracks a dozen states likely to determine the 2012 presidential election.

Swing states' independents are warming up to Obama, supporting the president over Romney, 48-40, and Santorum, 50-39, after trailing the GOP field among these voters over the last month, Purple Strategies' polling memo said.

The pollster has been surveying likely voters in states that are likely to be heavily contested in November, such as the West's Colorado, Nevada, New Mexico; Iowa Minnesota, Wisconsin, in the Heartland; New Hampshire, Ohio, Pennsylvania in the Rust Belt; and the South's Florida, North Carolina and Virginia.

Purple Strategies says Obama's rising poll numbers appear to be the result of a improving political climate for the incumbent.

For instance, women voters polled prefer the president over Romney by 10 percentage points amid the GOP efforts to allow employers to drop contraception-covering insurance and new state abortion laws that are criticized as invasive.

On the U.S. economy, more voters in the 12 swing states -- 39 percent -- say the U.S. economy is recovering, while 35 percent say things are getting worse, the poll said. Nearly a quarter said the economy is flatlining. Facing rising gas prices, half of the voters polled would not blame Obama if fuel gets more expensive.

Despite the favorable political terrain for Obama, Romney's standing among voters in swing states improved, too. The former Massachusetts governor's approval rating increased to 29 percent and his unfavorable rating dipped to 56 percent.

In a head-to-head matchup with Obama, Romney is in a dead heat in Western and Southern swing states.