They are at each others' throats already. And there are still nearly eight months to go. The battle between President Bush and presumptive Democratic nominee John Kerry (search) could become one of the longest and hardest-hitting of recent U.S. presidential races, and easily will be the most expensive.

How voters will handle this political onslaught is a question that strategists in both parties are pondering.

Will Americans soon grow weary of nonstop campaigning and constant television and radio ads?

Or will the long campaign help them get a clearer, more informed view of the president and his challenger?

With so much time and only a handful of central issues — jobs, Iraq, health care costs, fighting terrorism — the race "could become the most substantive campaign of modern memory," suggested Kathleen Hall Jamieson, director of the University of Pennsylvania's Annenberg Public Policy Center (search).

People will quickly tire of personal attacks and empty rhetoric, but if Bush and Kerry outline their differences in specific terms, as they have begun to do, it should increase public attention, Jamieson said.

But it's hard for many to see the race as anything other than a wearying slugfest for both sides.

"It's going to be a real barnburner," said Rich Bond, a former Republican National Committee (search) chairman. "We're seeing in March what we usually don't see until October."

Bond and other Republicans said Bush had little choice but to aggressively take aim at Kerry after being pounded by Democrats for months. The Bush campaign began airing ads this month that invoke the Sept. 11 terrorist attacks and accuse Kerry of seeking to raise taxes and scrimp on defense.

Polls show the country is nearly as divided now as it was during the legal battle over the 2000 election. Some show Kerry would win if the election were held today while others show Bush clinging to a slight edge.

With Kerry having emerged essentially unscathed from a crowded Democratic field and Bush now aiming his $100-billion-plus campaign machine directly at the Massachusetts senator, the general election contest already seems well under way.

Bush has gone after Kerry by name, something presidents seeking re-election rarely do so early, accusing him of flip-flopping on trade, the Iraq war and tax policy and accusing him of "tired, defeatist" solutions.

It's a risky strategy that could backfire if Bush is perceived as being desperate, analysts of both parties suggested.

Kerry has proposed rolling back Bush tax cuts on the wealthy, has accused the president of breaking his promises, misleading Americans on the Iraq war and being a divisive, polarizing figure.

His open-mike comments that Bush's Republicans were "the most crooked ... lying group I've ever seen" drew GOP demands for apologies and added to the bare-knuckles mood of the campaign.

Ads by pro-Democratic political groups accuse Bush of favoring the rich and "eroding the American dream." And Kerry's campaign was preparing an ad accusing Bush of misleading the nation and distorting the Democrat's record.

Republican pollster Bill McInturff and Democratic pollster Stanley Greenberg suggest the nation is in the grips of what they dubbed "Premature Partisan Polarization." In a recent joint survey, they noted that Bush had a 94 percent approval rating among Republicans. But only 16 percent of the Democrats in their poll said they approved of his job performance.

Carroll Doherty, an analyst for the Pew Research Center for the People and the Press, said the level of polarization in the country "exceeds that for President Clinton in September 1998, during the impeachment battle."

Republicans didn't expect a Democratic candidate this early, didn't expect it to be Kerry, didn't expect it to be done with minimal Democratic bloodshed and weren't expecting an increasingly restless Republican base.

Now, they're scurrying to try to define the four-term senator for the public before Kerry has a chance to define himself.

Bush campaign strategist and pollster Matthew Dowd said the wrap up of the Democratic nominating process presented "a window of opportunity" to begin making the case for Bush. He suggested the race would more closely resemble a marathon than a sprint to the finish.

"This is the political equivalent of the 100-year war," suggested Norman Ornstein of the American Enterprise Institute.