The Bush administration is reported to be investigating the possibility of postponing the presidential election in the event of a terror attack.
Security is a major issue in the upcoming US elections
US counter-terrorism officials are examining what steps would be needed to permit a delay, Newsweek reports.
Homeland Security chief Tom Ridge last week warned al-Qaeda was planning to attack the US to disrupt the poll but conceded he had no precise information.
A senior Democrat in Congress has said talk of postponement is "excessive".
In its latest edition, Newsweek reports that Mr Ridge has asked the Justice Department to examine what legal steps would be needed to permit the postponement of the 2 November election.
This follows a letter from the chairman of the new Election Assistance Commission, DeForest Soaries, who urged Mr Ridge to seek emergency legislation from Congress that would allow his agency to reschedule the vote in the event of an attack.
Mr Soaries noted that while New York's board of elections suspended primary elections on 11 September 2001, "the federal government has no agency that has the statutory authority to cancel and reschedule a federal election."
Homeland Security Department spokesman Brian Roehrkasse told Newsweek, "We are reviewing the issue to determine what steps need to be taken to secure the election."
Republican Representative Christopher Cox, who chairs the House Homeland Security Committee, told CNN that it was prudent to prepare for a postponement.
"These are doomsday scenarios. We don't have any intelligence to suggest that it is going to happen, but we're preparing for all of these contingencies now."
But Jane Harman, the senior Democrat on the House of Representatives Intelligence Committee, said proposing a postponement would be "excessive based on what we know".
She also criticised Mr Ridge's suggestion that al-Qaeda was planning to disrupt the election, saying the warning was based on old information.
The BBC's Justin Webb in Washington says the Democrats' unspoken fear is that the White House will play on the nerves of Americans as the election nears, hoping to gain support from a nation fearful of any change in course.
It is a difficult strategy for the Democrats to counter.
If they appeared complacent and terrorists did strike, they would be politically destroyed, he says.
No US presidential election has ever been postponed.
Abraham Lincoln was urged by some aides to suspend the election of 1864 - during the US Civil War - but despite the expectation that he would lose, he refused.
"The election is a necessity," Lincoln said. "We cannot have a free government without elections; and if the rebellion could force us to forgo, or postpone, a national election, it might fairly claim to have already conquered us."