WASHINGTON, Oct 24 (AFP) - George W. Bush and John Kerry headed to the climax of their marathon presidential campaign with their endgame pitch reduced to the most basic of questions -- who can keep America safe from terrorists.
With polls ahead of next week's election showing the race tight, especially in the state-by-state scramble for decisive electoral votes, national security has remained the main battlefield.
A new Time magazine survey showed terrorism and Iraq uppermost in the minds of 42 percent of voters, compared to a combined 38 percent for the economy and health care. The priorities were reversed a week earlier.
The Republicans have worked hard to keep the focus on security, with Bush campaigning as a "war president" after the September 11, 2001 attacks and blasting Kerry as weak, irresolute and clueless on terrorism.
For the final run, the president unveiled a new stump speech that sharpened his closing argument to "five commitments" to American families: security, family budgets, quality of life, retirement and values.
But the White House made it clear that Bush would continue "contrasting and clarifying the choices" facing US voters -- a euphemism for non-stop assaults on Kerry's credibility and fitness for command.
The tactic hit a new, menacing level Friday with a television spot that showed "terrorist" wolves in a forest ready to pounce while a female narrator murmured: "Weakness attracts those who are waiting to do America harm."
Kerry has fired back with increasingly harsh criticism of Bush's invasion of Iraq, which he called a "profound diversion" from the war on terror. He accused the president of misleading the public and refusing to acknowledge mistakes.
But if the Massachusetts senator once hoped to turn the spotlight on the economy and losses of US jobs, where Bush is vulnerable, he has been kept on the defensive by relentless Republican assaults on his leadership.
The decorated Vietnam war veteran virtually conceded last week the rest of the campaign would be fought on Bush's terms: "He wants to make it solely a contest on national security. Well, I welcome that debate."
The Kerry campaign felt more comfortable about the contest to knit together a majority of the 538 electoral votes that are apportioned among the states and awarded in separate, mostly winner-take-all races.
Bush's 271-266 victory of four years ago could be reversed by the flip of a single state. Most attention has been paid to Florida and Ohio, which narrowly voted Republican in 2000, and Pennsylvania, which went Democratic.
Polls showed the race close in all three but Democratic strategist Tad Devine was confident of a Kerry sweep, telling reporters, "Thats why the president now has his back against the wall."
Kerry also had hopes of using strictly local issues to pick off some other states, such as Nevada, where anger has mounted over plans to make the Yucca mountain a nuclear waste dump.
Bush set his sights on snatching previously Democratic states such as Iowa and Wisconsin in the Midwest, and the western state of New Mexico that went for his 2000 rival Al Gore by a scant 366 votes.
Both candidates revised their campaign plans daily but planned to devote most of their time in the coming days to the Midwest battleground. Kerry was expected to give particular attention to Ohio.
With the election hanging on a knife's edge, political experts said the key factor could be which sides does a better job of getting out the vote, notably in the critical swing states.
Registration drives and election-day mobilization squads have been organized and efforts mounted to bring in ballots from military personnel, expatriates and other absentee voters.
Bush and Kerry also honed their messages to energize their base.
The Republicans were going after evangelical Christians, the military vote, richer Americans and the rural population while the Democrats focused on young people, African Americans, Latinos and other staples of support.
The female vote was turning out to be an unexpectedly close fight; Gore won it by 11 points in 2000 but some polls show Bush tied with Kerry or even ahead, a worrisome sign for the Democrats.
And mindful of the spectacle in 2000, when the election hinged on a bitter recount dispute in Florida that went all the way to the US Supreme Court, the parties massed armies of lawyers to scrutinize the vote nationwide.
Another cliffhanger could produce challenges in several states which Curtis Gans, director of the Committee for the Study of the American Electorate, said would make the chaos in Florida "look like a picnic."

10/24/2004 10:04 GMT - AFP