President Barack Obama's lead in battleground states Colorado and Virginia have vanished in the past month, according to new NBC News-Wall Street Journal-Marist and Fox News polls of the states.

Obama is now tied with Republican Mitt Romney in Colorado among likely voters in the new NBC-WSJ-Marist poll, down from a 5-point lead in mid-September. In Virginia, a 7-point advantage in a September Fox News poll has crumbled, and Romney now leads by 2 points.

In Colorado, Obama has gotten slammed in the past month with Independents. An 11-point lead last month has slimmed to a virtual tie. Romney has also expanded his lead to 13 points among men and closed the gap to just a 3-point disadvantage among women. Obama and Romney met for the first debate in Denver, where Romney won handily.

Independents have also moved toward Romney in Virginia. They now prefer him by an astounding 22 points, compared with an even split last month. Obama's lead with women in the state has been cut in half to just 6 points.

Significantly, though, the NBC-WSJ polls also show that Obama has maintained a 50-47 lead in battleground state Nevada, which mirrors a result from Public Policy Polling released yesterday. If Obama is able to hold onto Nevada along with Wisconsin and Ohio (two places where he is currently leading polling), he would be on track to 270 electoral votes.