GOP presidential hopeful Ron Paul is launching a $1 million ad campaign in key early states, as he seeks to shake up a race being dominated by Rick Perry and Mitt Romney.

The Texas congressman's new ad highlights his efforts on behalf of two Vietnam veterans, who call him "a veteran's best friend."

The 60-second spot is scheduled to air tonight during the GOP presidential debate on Fox News, and Paul's campaign says it will be played "heavily" in Iowa, New Hampshire, South Carolina and Nevada.

The three-week ad buy is significant, as Paul moves up to second place in a newly released New Hampshire poll -- albeit with Mitt Romney maintaining a huge lead over the GOP field. Paul, a libertarian-thinking Republican, comes in third behind Perry and Romney in most national polls, according to the surveys compiled by the RealClearPolitics website.

"Our campaign is seeing growing momentum now and is doing this ad blitz to cement ourselves in the top tier," Paul campaign manager Jesse Benton said.

The ad is an emotional one, featuring Army veterans Joe Pena and Rene Reyes recounting a battle in which they said 75 soldiers were killed and 115 wounded.

"We had never been thanked for our services. Never," Pena says in the spot. "Congressman Ron Paul got my medals for me and presented them to me. That was an awesome feeling."

The spot also makes reference to Paul being a veteran. He was a flight surgeon in the U.S. Air Force in the early 1960s and then served in the Air National Guard.