A new poll shows John McCain made gains on Barack Obama in four key November battleground states -- Colorado, Michigan, Minnesota and Wisconsin -- giving McCain a slight edge in one state, and chipping away at Obama's lead in the others.

The Quinnipiac University/Wall Street Journal/WashingtonPost.com poll showed McCain tentatively ahead of Obama in Colorado by 2 percentage points, with McCain at 46 percentage points, and Obama at 44. One month ago, Obama held 49-44 percent lead.

McCain's biggest gain in the other three states was in Minnesota. In June, Obama held a 17 percentage-point lead over his rival; this month, the split had dwindled to 46-44 in favor of Obama.

In Michigan and Wisconsin, McCain's earnings came in the form of Obama's losses. In both states, Obama lost

2 percentage points of support from a month earlier. The July Michigan data showed Obama with a 46-42 percent lead; the Wisconsin numbers put Obama with a 50-39 percent lead.

The July 14-22 surveys quizzed likely voters. The margin of error in Colorado was +/- 2.6 percent; in Michigan, +/- 2.4 percent; in Minnesota, +/- 2.8 percent; and in Wisconsin, +/- 3 percent.

Click here to see more information on the poll at Quinnipiac University.