A new USA Today/Gallup poll shows President Obama with a widening gap over Willard M. Romney among registered voters in a dozen swing states. Obama’s commanding a strong lead with 51 points — that’s nine ahead of Romney’s 42 percent. Obama can thank women under 50 for the jump. In February, 49 percent of women supported the president while 44 percent sided with the former Massachusetts governor. Now, 61 percent of women under 50 support Obama, while only 30 percent support Romney.