WASHINGTON -- U.S. House Republicans will gather at noon today in a large Capitol Hill meeting room to nominate a new Speaker of the House, amid unrest in the conservative base about whether John Boehner's departure will really change all that much.

Majority Leader Kevin McCarthy is the odds-on favorite to win today's closed-door vote, but his margin of victory will be key. McCarthy's foes could have the votes to keep McCarthy away from the required 218 in an open floor vote Oct. 29 -- assuming no Democrats back him, as is the norm. That would provoke another closed-door caucus meeting, further turmoil, and likely extend the reign of Boehner, as the nation is due to breach the debt ceiling a few days later.

The House Freedom Caucus, the group of most-conservative members who helped force Boehner's retirement, endorsed Rep. Daniel Webster, R-Fla., on Wednesday. Georgia freshmen Reps. Barry Loudermilk, R-Cassville; and Jody Hice, R-Monroe; are members of the group, meaning they'll likely support Webster behind closed doors, but it's still unclear what will happen on the floor.

Some conservative groups are rallying supporters to oppose McCarthy. Former Georgia Rep. Paul Broun, R-Athens, who might have bigger things to worry about these days, had his name attached to a mass email trying to get petition signers to "Fire McCarthy" as speaker, before he even wins the post. From the missive:

"While he's doing everything possible to install Kevin McCarthy as his replacement as House Speaker, he knows he can't succeed in light of our national campaign."

Conservative activist Joe McCutchen, of Ellijay, has been relentlessly calling talk shows and congressmen with the same message.

"McCarthy would be just like having Boehner," said McCutchen, who said he has called Loudermilk, Rep. Doug Collins, R-Gainesville; and  Rep. Tom Graves, R-Ranger; to urge votes against McCarthy. In addition, McCutchen said he is "definitely trying to fire people up to get on the Internet and get on talk shows."

The question is whether the easygoing, lesser-known McCarthy provokes the same kind of animus in the base as Boehner. Hice, Loudermilk and Rep. Rick Allen, R-Evans, pledged to vote against Boehner when running for their seats last year. All three said they voiced a "no" in a closed-door voice vote in November, but then supported Boehner on the floor in January because there was no viable alternative.

They heard an earful from their constituents afterward. Allen, who took many an anti-Boehner call, said he has heard from a lot of constituents on this speaker race, and "they have the confidence in me that I'll make the right decision." Allen indicated that he had a choice in mind to "unify" the GOP, but he wouldn't share it Wednesday:

"I like to keep my powder dry because, again, things change here by the minute. And so you say one thing one day and you end up having to say: 'Oh, this is what I really meant.' You tell me: Who do you think's going to win?"

Easy answer, if you ask Rep. Austin Scott, R-Tifton: McCarthy.

When McCarthy moved up the ladder last year, Scott supported Raul Labrador, R-Idaho, for majority leader. Labrador was the more-conservative outsider choice at the time, but Scott said he's been impressed by McCarthy's tenure in the majority leader seat:

"It's Kevin when there is a disagreement in the conference [who] has everybody from different groups come and sit around in the conference table, and about 20 members. He, quite honestly, when I've watched him in those meetings, they're very open. They're not steering you towards their position. Good leaders listen and Kevin's been willing to listen, so I'm comfortable with giving him the chance to be speaker."

McCarthy's elevation also would open up the majority leader slot for Scott's delegation-mate, Rep. Tom Price, R-Roswell. Scott said he's supporting Price for the post.