(Angus Reid Global Monitor) - Democrat Barack Obama is ahead of Republican John McCain in the United States, according to a poll by Zogby Interactive. 43 per cent of respondents would vote for the Illinois senator in this year's presidential ballot, while 40 per cent would back Republican Arizona senator John McCain.

Libertarian nominee Bob Barr is third with six per cent, followed by independent candidate Ralph Nader with two per cent. Nine per cent of respondents are undecided, or would vote for other contenders.