In the ad, Republican Gerlach comes out swinging: "When I believe President Bush is right, I'm behind him. But when I think he's wrong, I let him know that, too," Gerlach says in the opening moments. The new 30-second spot features the congressman disagreeing with Bush on his guest-worker program and calling for tougher security measures. "The president wants a guest-worker program that may lead to amnesty for illegal immigrants," he says. "That's sending the wrong message at the wrong time."

But Democratic challenger Lois Murphy says the ad is only a sign of weakness. "The fact that he is buying television time so early in the campaign seems to show that he is nervous about how the race is going," says Mark Nevins, Murphy's spokesman. She has answered with her own blistery TV ad riposte, which replays the opening lines of Gerlach's ad and then criticizes his support of drug companies, tax breaks for "big oil," and the Central American Free Trade Agreement.

Whatever the dueling ads mean to political tea-leaf readers, there is no doubt that time costs money. And all campaign war chests, however deep, have their limits. According to the Center for Responsive Politics, Gerlach has raised $1,796,862 and spent $850,598 thus far. Most of his money, 52 percent, has come from political action committees. Meanwhile, Murphy has pulled in $1,418,998 and spent $493,975. Most of her money, 81 percent, has come from individual donors.–Alex Kingsbury