House speaker candidate Tom Emmer, the GOP whip, has moved to lock in support across the ideological and geographic spectrum in the conference, giving him what many House Republicans believe is an advantage heading into a secret-ballot election to nominate their candidate Tuesday, according to Republican sources.

But it's hard to assess his chances fully since it's a crowded field, with at least seven candidates working the phones all weekend to win a majority of support within the conference.

Even if Emmer were to win the nomination, Republican sources are uncertain he can get 217 votes on the floor, as he could face resistance from members of the hardline House Freedom Caucus skeptical of the GOP leadership team.

House Republicans are searching for a new GOP speaker nominee after Rep. Jim Jordan on Friday became the latest exit from the race. The chamber has been without a speaker for more than two weeks after Kevin McCarthy's historic ouster this month.

Emmer, of Minnesota, said in a letter to colleagues Saturday that he was seeking the speakership with the goal of delivering "historic change." McCarthy has endorsed Emmer for speaker, delivering an early boost for his candidacy.

McCarthy on Sunday urged his House colleagues to elect Emmer but stopped short of ruling out another speakership run himself.

"He's been in the room with all of our successes," the California Republican said of Emmer. "He sets himself head and shoulders above all those others who want to run.

"This is not a time for a learning experience as speaker. Tom would be able to walk into the job and do it on Day 1," McCarthy said on NBC's "Meet the Press."

McCarthy once again demurred when asked about returning to wield the gavel.

"I don't need the title. I'm going to help in any way I can," he said. "I'm supporting Tom Emmer, but I'm going to tell you, I'm still a member of Congress, and I'm going to lead in any capacity I can to help to protect America."