Democratic presidential candidate Barack Obama is leading Republican John McCain in four battleground states, according to a survey released that pollsters say could point to a broad Obama victory in November.
The Quinnipiac University poll found Obama leading McCain in Colorado, Michigan, Minnesota and Wisconsin, which strategists view as among the closely fought states that could determine the outcome of the race.
"If these numbers were to hold, it would be very difficult to see how Senator Obama doesn't win the presidency by a very comfortable margin," said Peter Brown, assistant director of the poll.
The poll found Obama leads 49 to 44 per cent in Colorado, 48 to 42 per cent in Michigan, 52 to 39 per cent in Wisconsin and 54 to 37 per cent in Minnesota. The margin of error in each state was around 2.6 percentage points.
The US presidential race is not determined by a simple popular vote, but instead by counting the electoral votes of the states each candidate wins. Populous California has 55 electoral votes, while sparsely populated Montana has three. A total of 270 is needed for victory.
Candidates recently devoted most of their campaigning to a handful of "swing" states that could line up behind either candidate.
A Quinnipiac poll last week found Obama leading McCain in the largest swing states - Ohio, Florida and Pennsylvania.
In this week's poll, Obama held strong leads among women, minorities, independent voters and young voters. McCain led among men in Colorado and white voters in Michigan, where Obama's overall lead was narrower. Roughly three-quarters of those polled said their minds were made up.
