Successors line up after U.S. Speaker's shock resignation

John Boehner's sudden resignation is launching an unexpected leadership battle in Congress that may be a turning point for Republicans, likely pitting the establishment wing against tea party conservatives. The Ohio Republican, who has served as the Speaker of the House since 2011, told colleagues in a closed-door gathering Friday morning that he would leave at the end of October, sending shockwaves through the chamber. Even as Boehner's fellow lawmakers were still digesting the news, the speculation over who would succeed him had already begun. One person who is naturally next in line is House Majority Leader Kevin McCarthy, but this could be a moment for the tea party to make a splash. Ohio GOP Rep. Steve Chabot, who described the mood in the room as "somber" and said there had been tears from Boehner, said the subject of who would replace the Speaker had not come up. But he predicted that this would begin in "five minutes." If McCarthy wins the gavel, it would mark the continuation of an incredible ascent for the California Republican, who has only held the second highest ranking job in the House since last summer. McCarthy himself was only said to have found out about Boehner's resignation moments before Friday's morning meeting. During his press conference Friday afternoon, Boehner effectively endorsed McCarthy. "I am not going to be here to vote on the next Speaker. But that's up to the next members. But having said that, I think that Kevin McCarthy would make an excellent Speaker," Boehner said. Two sources familiar with McCarthy's lobbying efforts told CNN Friday night that they feel he's in a good place to get the votes to become Speaker. He spent the whole day talking to people and will continue to talk to every single member of the GOP conference, the sources said. Although he's part of the "establishment" leadership, he has good relationships with many of the newer members, many of whom he helped recruit. One of the sources said there's going to be an effort to make sure House Republicans have a good understanding of who McCarthy is and where he came from, defining him before others can do it for him. The source cited accusations that he is pro-amnesty on immigration as an area in particular that they want to defend him over. But McCarthy is expected to face a challenge for the speakership, though it's unclear how serious that fight will be. The chamber's conservative faction may instead choose to focus on winning another post -- such as majority leader or whip -- instead. Among the lawmakers who could seek the majority leader spot are Reps. Steve Scalise of Louisiana (the current Whip), Cathy McMorris Rodgers of Washington state and Tom Price of Georgia. Lawmakers react to Boehner's announcement Deputy Whip Patrick McHenry, R-North Carolina, is a leading candidate to be the next whip, and Rep. Markwayne Mullin of Oklahoma has also indicated he will seek the role. Scalise held a conference call Friday night with his whip team to tell the House vote counters that he will run for majority leader if McCarthy were to become speaker, according to a source with knowledge of the call. As majority leader, Scalise said he would work with every Republican to advance conservative legislation, and said he would ensure the House took the steps to develop consensus within the caucus. Scalise added that Boehner's decision to resign was "one of the most selfless things I've ever seen." On Saturday, Rep. Peter Roskam, R-Illinois, called for a special conference meeting head of the vote for the next Speaker. "Healing our divisions and uniting behind the conservative policy solutions the American people deserve will help our members and it will empower the new leaders we select," he said in a letter to colleagues. Roskam said he was not announcing a run for any leadership position, but several House Republicans said he is making calls and positioning to join the race for majority leader.