Enlarge Bob Daemmrich

Republican candidate Mitt Romney waves to the crowd at the CNN Charleston debates on January 19, 2012.

Mitt Romney has snagged the endorsements of three Texas congressmen, including the chairman of the National Republican Congressional Committee.

U.S. Reps. Pete Sessions, R-Dallas, head of the NRCC; John Carter, R-Georgetown; and Mac Thornberry, R-Clarendon, have thrown their support behind the former Massachusetts governor, the Romney campaign is announcing Thursday. Last week, Romney was in Houston picking up the endorsement of former President George H.W. Bush; he previously announced a nod from Texas House Speaker Joe Straus, R-San Antonio.

Romney said in a press release that the three congressmen endorsing him Thursday “come from a long line of great conservative leaders.” He did not mention his chief Republican rival, former Pennsylvania Sen. Rick Santorum, who remains in the presidential race despite the longest of odds.

Santorum is hoping a good showing in the May 29 Texas primary will help make him a viable challenger at the party's August convention in Tampa, but the delegate math is stacked against him.

Sessions, echoing the sentiments of others in the GOP establishment, said Republicans “must unite behind the one candidate who can lead our party, win in November, and put in place conservative pro-growth policies to restart our economy.”

“Texans can be sure that they will have a friend of job creators with Mitt Romney in the White House,” he said.

Gov. Rick Perry endorsed Newt Gingrich after dropping his own White House bid on Jan. 19, but the former U.S. House speaker is no longer considered a plausible candidate.