With five months to go for the US Presidential election, presumptive Democratic nominee Barack Obama and Republican John McCain are locked in a statistical dead heat with more than one in five voters acknowledging that they might change their mind between now and November, an opinion poll showed.
Analysts agreed that polls five months before the election may not be indicative of the final outcome but would be watched closely by the candidates.
In the CNN/Opinion Research Corporation poll, the first conducted entirely after Obama became the presumptive Democratic nominee, he leads his Republican counterpart 49 per cent to 46 per cent among registered voters -- a statistical tie, given the 3-point margin of error.
McCain and Obama are not alone. Independent candidate Ralph Nader and Republican-turned-Libertarian Bob Barr are vying with the two major-party candidates for independent voters.
But at this point, the poll says it looks unlikely either will play a spoiler role. When pollsters asked about a field of candidates that includes Nader and Barr, the margin between Obama and McCain was virtually unchanged, with Democrat leading 47 per cent to 43 percent. Nader pulls in 6 per cent and Barr 2.
A hypothetical Obama-Hillary Clinton ticket would currently get 52 per cent of the vote, compared with 46 per cent for a hypothetical McCain-Mitt Romney ticket, according to the poll.
If Clinton is not on the ticket, 60 per cent of her Democratic supporters said they would vote for Obama, 17 per cent would vote for McCain, and 22 per cent would stay at home in November and not vote for anyone.
"That's just one estimate of the 'Clinton factor,' " said CNN polling director Keating Holland, "and it may not be an accurate predictor since it piles several hypotheticals on top of each other and asks people to guess their state of mind five months from now."
Nonetheless, it does indicate that unmotivated Clinton supporters may be a bigger risk to Obama than defections from the Clinton camp to McCain.