By Steve Holland and Thomas Ferraro

Washington - The government has done "a helluva job" guarding America, Vice President Dick Cheney said on Sunday, as President George Bush prepared to visit Ground Zero amid an election-year debate on whether the country is safer five years after the September 11 attacks.

Cheney and other top administration officials sought on the eve of the anniversary to promote what they say is progress in protecting against a second September 11.

Democrats countered that the administration had used the attacks for political gain, underlining the bitter divisions that have emerged since the attacks on New York and Washington killed nearly 3 000 people and united the nation in grief.

"I don't know how you can explain five years of no attacks, five years of successful disruption of attacks, five years of defeating the efforts of al-Qaeda to come back and kill more Americans. You have got to give some credence to the notion that maybe somebody did something right," Cheney told NBC's Meet The Press.

He added: "We've done a helluva job here at home in terms of homeland security."

But many Americans have doubts. ABC News said a poll it conducted found the number of Americans who think the country is safer now than four years ago had dropped to about 52 percent from around 88 percent previously.

Democrats charge the Iraq war has sucked away billions of dollars that could have been spent to improve domestic security, served as a breeding ground for terrorists, left Osama bin Laden still at large and exposed Afghanistan's US-backed government to a renewed threat from the Taliban.

Democratic National Committee Chairman Howard Dean said Bush had used the attacks for political gain ahead of November elections in which Democrats see a good chance to take control of one or both chambers of the US Congress from Republicans.

"We think the president has played too much politics," he said. "They think they can't win the elections unless they talk about terrorism all the time."

Dean said the administration had got bogged down in Iraq when it should have been going "full-scale" after Osama bin Laden.

The Washington Post reported on Sunday that the trail for Bin Laden has gone "stone cold" and that US commandos looking for him have not received a credible lead on his whereabouts in more than two years.