Jon Huntsman’s presidential campaign released an advertisement on Thursday that highlights Ron Paul's highly controversial newsletters and questions his electability.

Paul is the GOP’s leading presidential candidate in the crucial Iowa caucuses, but has been plagued by racist, hate-filled newsletters that were published under his name. The newsletters were published about 20 years ago and contained a number of incendiary comments about African-Americans, gays and Israel. All of the newsletters featured his name, but Paul has said he did not edit or write the controversial language.

Huntsman's ad begins with a clip of Paul talking about the newsletters in 1996 and then transitions to media reports about its racist and homophobic contents. The ad concludes with a slide that asks, "Can New Hampshire voters really trust Ron Paul?"

Paul has surpassed Newt Gingrich in New Hampshire, according to Public Policy Polling, and is now firmly in second place. But he is currently 15 points behind Mitt Romney.

“Rep. Paul’s newsletters raise serious questions about his judgment, character and whether New Hampshire voters can trust him to lead,” Huntsman spokesman Tim Miller said in a news release.

Watch the ad, uploaded to YouTube, below: