Paul slams Gingrich and Romney as part of the "machine" in new ad

Rep. Ron Paul's rivals for the Republican presidential nomination can't seem to resist taking shots at the libertarian congressman as he climbs to the top of the polls in Iowa -- but Paul isn't afraid to hit back.

In his latest television ad, called "Machine," Paul blames the Washington culture of "politicians who supported bailouts and mandates, serial hypocrites and flip floppers," for strangling the economy. The narrative is combined with images of Newt Gingrich and Mitt Romney.

Both Gingrich and Romney have in the past expressed support for the 2008 financial bailout and health insurance mandates (though both now say they oppose the nationwide mandate President Obama signed into law) -- two controversial issues with the GOP base.

Paul's ad casts the congressman -- who has served on Capitol Hill since the 1970's -- as an iconoclast who can fight the "Washington machine." The ad highlights points from Paul's economic plan, which aims to cut $1 trillion in government spending in one year and balance the federal budget in three years.

With less than one week to go before the Iowa caucuses -- and polls showing that Paul is a leading candidate in the Hawkeye state -- Paul's rivals are trying to turn his libertarian values from an asset into a liability.

At an Iowa event Wednesday morning, Romney criticized Paul's foreign policy views without directly naming the congressman.

"One of the people running for president thinks it's okay for Iran to have a nuclear weapon," Romney said.

Paul has said it would be unwise for the U.S. to try to stop Iran from acquiring a nuclear weapon.

In a Tuesday evening interview on CNN, Gingrich also slammed Paul on the issue, saying, "If you think it doesn't matter for the Iranians to get a nuclear weapon, then Ron Paul might be your candidate."

Texas Gov. Rick Perry and Rep. Michele Bachmann took similar swipes at Paul this week. Ron Paul would be dangerous for the United States on foreign policy," Bachmann told CBS News.

Additional reporting by CBS News/ National Journal campaign reporter Sarah B. Boxer.