Des Moines, Iowa (CNN) - Turn on the TV here in the Hawkeye State, and you'll get inundated with a barrage of Republican presidential campaign commercials, with many of them negative in nature.

"If Washington's the problem," says the narrator in an ad by Texas Gov. Rick Perry's campaign, "why trust a congressman to fix it?" The ad goes on to criticize rival candidates Rep. Ron Paul of Texas, Rep. Michele Bachmann of neighboring Minnesota, former House Speaker Newt Gingrich and former Sen. Rick Santorum of Pennsylvania. "Among them, they've spent 63 years in Congress, leaving us with debt, earmarks and bailouts."