Through next week, President Bush (search), Democratic rival John Kerry (search) and liberal interest groups will have spent at least $90 million to air television ads since early March — a whopping total for an election that's still about six months away.

Campaign commercials started early and spending already has reached levels that typically aren't seen until after Labor Day.

So, why so many ads now?

Bush and Kerry — as well as Democratic-leaning interest groups — are broadcasting commercials not necessarily to secure votes on Nov. 2, but rather to set the stage for the rest of the campaign and to energize core supporters for what both parties expect will be an extremely close election.

The candidates also are running unprecedented amounts of ads early for financial reasons: They aren't constrained by spending limits that they would have faced had they accepted public financing and they are raising hefty amounts of money that must be spent before their party conventions this summer.

"They're behaving right now as if it's September," said Kathleen Hall Jamieson, director of the University of Pennsylvania's Annenberg Public Policy Center (search).

In just seven weeks: Bush will have spent at least $50 million; Kerry will have spent about $12 million; and Democratic-leaning groups, including the Media Fund, MoveOn.org's affiliates and the AFL-CIO, will have poured in at least $28 million.

That's far more than the $77 million that Bush, Democrat Al Gore, the Republican Party, the Democratic Party and interest groups supporting both candidates spent over four months — from June through September — in 2000, according to New York University Law School's Brennan Center for Justice.

So far, Bush's re-election ads have run at least 35,000 times, mostly in 18 competitive states but also nationally on some cable networks, while Kerry's ads have appeared more than 12,000 times in 17 states, according to TNS Media Intelligence/Campaign Media Analysis Group, a Virginia-based nonpartisan organization that tracks ads. Commercials by liberal interest groups have run thousands of times as well.

Political analysts and media experts agree that ads airing now probably won't directly affect how people vote in November.

"In some sense what this advertising does is provide an ever-unfolding dialogue over a couple months," said John Geer, a Vanderbilt University professor who has studied 40 years worth of presidential campaign ads. "A presidential election year is very much like a 15-round fight, and we're in the first few rounds."

Bush kicked off the general election ad wars March 4, just two days after Kerry secured the Democratic nomination. The incumbent Republican's first few re-election ads were optimistic commercials that portrayed him as having "steady leadership in times of change" and spots that depicted Kerry as weak on the economy and terrorism.

The president is drastically cutting back his TV ads this week in 18 states because, the campaign says, voters aren't tuned in to the presidential race right now.

Democrats argue that Bush's ads haven't been as effective as Bush advisers had hoped, and point to independent polls that show the race virtually even. However, polls also show that Kerry's unfavorable ratings have increased, which pollsters attribute to both the ads and attacks on the campaign trail.

When Bush started running commercials, Democratic-leaning groups that operate independently from Kerry's campaign started running moderate levels of anti-Bush ads.

Kerry went on the air as well, initially to respond to Bush's ads. He plans to intensify his advertising spending soon with ads designed to tell voters his biography and proposals.

However, Kerry, too, is scaling back his ads next week as his staff prepares for the bigger ad launch the following week.

That's good news for people tired of so many campaign ads. They may get somewhat of a breather — at least next week.