A new poll shows President Obama with an advantage over increasingly-likely GOP candidate Mitt Romney in a dozen key battleground states.

The USA Today/Gallup poll shows Obama with 51 percent support in key swing states, while Romney has 42 percent. Obama's lead is smaller nationally--49 percent to 45 percent--but higher than a month ago when the men were tied.

Obama's greatest advantage over Romney is with women, particularly women under 50. Support swings two for one towards the president among voters in that demographic. Obama enjoys 60 percent support with women under 50, Romney, only 30 percent.

Predictably, Democrats largely back the president, according to the poll, while a large majority of Republicans support Romney. Among independents, vital to the election, Obama bests Romney 48 percent to 40 percent. Twelve percent of independents say they are still undecided.

The poll surveyed 901 registered voters nationwide, and 933 voters specifically from the battleground states of: Colorado, Florida, Iowa, Michigan, Nevada, New Hampshire, New Mexico, North Carolina, Ohio, Pennsylvania, Virginia and Wisconsin. The margin of error is plus or minus 4 percent.