Rep. Raul Labrador returned to Capitol Hill on Tuesday to formally begin rounding up support from fellow GOP lawmakers in his uphill bid to become majority leader.

But with an opponent who has served as majority whip since 2011 and who has already rounded up the votes of much of the GOP establishment, it may be impossible for Labrador to seriously threaten an easy victory for Rep. Kevin McCarthy.

McCarthy, of California, has the implicit backing of the GOP leadership, including current Majority Leader Eric Cantor, R-Va., who is stepping down from the post after a shocking primary loss last week. House Speaker John Boehner, R-Ohio, has not officially thrown his support behind either candidate.

McCarthy’s team claims to have gathered the support of more than half of the GOP conference, and many lawmakers said they expected McCarthy would beat Labrador by a sizable margin.

The leadership elections are scheduled for June 19.

“I think Kevin is in a good position,” Rep. John Shimkus, R-Ill., told the Washington Examiner.

Labrador is forging ahead, however. He told the Examiner he is “absolutely” gaining on McCarthy and his chances “are looking really good.”

Elected from Idaho during the 2010 Tea Party wave, Labrador announced his candidacy on Friday in a memo to lawmakers, telling them he believes the House Republican conference needs a alternative voice in leadership.

Labrador cited Cantor's loss to Dave Brat, who beat Cantor in Virginia's 7th Congressional District by running as an anti-establishment candidate.

“Americans are looking for a change in the status quo,” he told colleagues in the memo.

Earlier Tuesday, Labrador huddled with 10 GOP lawmakers who are serving in his campaign whip operation, fanning out to build support among conservatives who are fed up with the policies and politics of the longtime GOP leadership establishment.

“I think he is getting a lot better reception than initially anticipated,” Rep. Matt Salmon, R-Ariz., who serves on Labrador’s whip team, said.

But some lawmakers are predicting Labrador will only win over about 30 Republicans, a far cry from the 117 he needs to beat McCarthy, the clear favorite among longtime members.

“I thought that was a done deal,” Rep. Don Young, R-Alaska, a McCarthy backer, said mockingly when asked who he would pick for majority leader on Thursday.

While Labrador may be too conservative for mainstream GOP members, his stance on immigration has hurt him with some lawmakers on the right, which could cost him more votes. Labrador supports creation of of a guest worker program for immigrant agricultural workers and would not rule out taking up immigration reform legislation at some point.

“I might have to do a write-in,” Rep. Steve King, R-Iowa, a staunch immigration opponent, said when asked if he would support Labrador.

Natural Resources Committee Chairman Rep. Doc Hastings, R-Wash., said Labrador’s candidacy will help the conference air out differences, but ultimately McCarthy — who he supports — will win.

“Raul says he thinks he can win,” Hastings said. “I don’t think he thinks he can win. But, I believe it is important, so that people don’t feel their issues are being addressed, that they make a statement.”