Tim Pawlenty this morning endorsed former rival Mitt Romney in the race for the Republican presidential nomination, telling Fox News that the former Massachusetts governor offered the GOP its best chance to defeat President Barack Obama in 2012.

Pawlenty, the former Minnesota governor, dropped out of the presidential race in August after a poor showing in the Ames straw poll followed up months of lackluster performance in the contest overall. Prior to dropping out, Pawlenty attacked Romney only sparingly despite the fact that the Massachusetts Republican appeared to be his main competition early on in the race. That was among the major knocks against Pawlenty’s candidacy but might have smoothed the way for his backing, which he delivered from Charleston, S.C.

“I believe he’s going to be a transformational president for this country,” said Pawlenty, who will serve as a national co-chairman of the Romney campaign.

Romney is now locked in a battle with Texas Gov. Rick Perry, who entered the GOP White House contest the same weekend that Pawlenty exited. Although Pawlenty’s endorsement might not move Republican primary voters, it could provide Romney with a boost in some of the key early states vis-a-vis the inside game and the fierce competition for top campaign strategists and major donors. Romney said in a statement that he was honored to receive Pawlenty’s backing.

“It is an honor to have Governor Pawlenty’s support,” Romney said in a statement. “Tim will be a trusted adviser as I move forward with my campaign. Tim has always been an advocate for lower taxes, reduced spending, and an environment where jobs can be created.”

Pawlenty said on Fox News that he remains uninterested in accepting any invitation he might receive to serve as the eventual nominee’s vice presidential running mate.