SENIOR Republicans believe that Senator John McCain is doomed to a landslide defeat that will hand Barack Obama more political power than any president in a generation.

The prospect of an electoral rout has unleashed bitter recriminations both within the McCain campaign and the wider conservative movement. Senator McCain is facing calls to sacrifice his own dwindling hopes and focus on saving vulnerable Republican Senate seats.

The fear is that Democratic candidates riding on Senator Obama's popularity may win the nine extra seats they need in the Senate to give them unfettered power in Congress. If the Democratic majority is big enough - at least 60 seats to 40 - Republicans would be unable to block legislation. No president has had the support of such a majority since Jimmy Carter won the 1976 election.

Former Bush speechwriter David Frum said Republicans should concentrate all their fire on "the need for balanced government".

"This could look like an ideological as well as a party victory if we're not careful," he said. "It could be 1980 in reverse. With this huge new role for federal government in the economy, the possibility for mischief-making is very, very great."