— The surprise end Thursday to U.S. House Majority Leader Kevin McCarthy’s race for House speaker seems likely to pull the plug on another Republican leadership campaign as well: The bid by House Majority Whip Steve Scalise to succeed McCarthy in the No. 2 post in the hierarchy.

Scalise, of Jefferson, had no immediate comment on McCarthy’s announcement, which left the House Republican majority in disarray — and the path to electing a new speaker uncertain. Two other House Republicans — Jason Chaffetz, of Utah, and Daniel Webster, of Florida — have declared their candidacies for speaker, but McCarthy, of California, was considered the overwhelming favorite to win the endorsement Thursday of the House Republican Conference, the official organization of the party’s members. McCarthy’s stunner at the opening of the conference meeting brought it to an abrupt end.

The post of speaker is a constitutional one, and the speaker is elected by the full House. Outgoing Speaker John Boehner, of Ohio, had set that vote for Oct. 29, but he indicated it would be postponed.

That leaves several weeks for other potential challengers to jump in the speaker’s race — including, potentially, Scalise. But as an incumbent member of the leadership, Scalise could encounter the same difficulties that helped derail McCarthy — and Boehner, whose announcement Sept. 27 that he would step down Oct. 30 was a surprise of its own. Boehner now seems likely to stay in the job beyond this month.

Boehner’s decision to quit was fueled by a right-wing revolt in the Republican ranks, centered in the House Freedom Caucus, an organization of about 40 deeply conservative members created early this year to drive the party’s agenda to the right.

Freedom Caucus members and some of their allies are dissatisfied with Boehner’s tactics on controversial issues such as defunding Planned Parenthood, the Iran nuclear deal and Democratic President Barack Obama’s executive orders on undocumented immigrants. Despite majorities in both the House and Senate, the Republicans are not strong enough to steamroll Senate Democrats, under the Senate’s rules, nor to override presidential vetoes.

Boehner prefers to avoid going to the mat with Democrats and risking a government shutdown, like the 16-day stoppage in 2013 that accomplished little and that moderate Republicans say hurt the party’s brand. But many in the Freedom Caucus want to push the Democrats to the limit — and they say their constituents demand it.

The dynamic for elections for speaker is considerably different than that for majority leader, whip and other internal leadership positions. To win as majority leader, for example, a candidate needs to capture the support of a majority of the Republicans in the House. But to get elected speaker, a candidate must carry a majority of the entire 435-seat House.

Republicans now hold one of their largest margins ever, 247-188 over the Democrats. But the Democrats likely will vote for their own leader, Nancy Pelosi, of California, as speaker, meaning a defection of 30 Republicans from their party’s nominee would deny him or her the majority needed.

It was the prospect of just that sort of defection that played into Boehner’s decision to resign. And it apparently triggered the withdrawal of McCarthy, who said he was not the person to unify the party.

The Freedom Caucus endorsed Webster on Wednesday. But if it has the power to upset the applecart, it is well short of the numbers needed to install its favored candidate as speaker.

In the 2014 election for whip, which was set off by another Republican shake-up, Scalise defeated two other contenders as a proven conservative from a red state, promising to bring that perspective to a leadership team that otherwise includes blue-state Republicans.

But as a loyal member of leadership, he has more than once voted Boehner’s way in opposition to the conservative confrontationalists, allying with Democrats to pass legislation opposed by a majority of Republicans, including every other House Republican from Louisiana. Such was the case Sept. 30, when the House passed a stopgap federal-government financing measure that did not defund Planned Parenthood, as conservatives ished.

Another, broader source of concern is Scalise’s 2002 speech in Metairie, while a state representative, to a group that had gathered for a meeting of a white-supremacist organization founded by neo-Nazi David Duke.

The controversy over that speech erupted in late 2014, when a Louisiana blogger spotlighted the event. Scalise said he did not know of any Duke links among his audience and that he regretted his appearance. Although some Democrats urged his resignation — and their sniping at Scalise has continued — Boehner and McCarthy stood by him, and he weathered the crisis. But the spotlight on the House speaker shines brightly, and some Republicans may be wary of negative public-relations fallout from any renewed focus on the incident.

Bob Livingston, a Washington lobbyist and former Republican congressman from New Orleans who was on the verge of election as speaker in 1998, said Thursday he anticipates that Scalise will decline to run for speaker and remain majority whip. Livingston was nominated by the Republican majority in 1998, virtually assuring his election, but withdrew within days of that endorsement following revelations of his involvement in an extramarital affair. An out-of-nowhere candidate, Dennis Hastert, of Illinois, was elected speaker.

If any consensus candidate for speaker emerged Thursday, it is Paul Ryan, the well-respected chairman of the Ways & Means Committee who ran for vice president on the national Republican ticket in 2012. Boehner talked to him twice during the day about entering the contest, a Republican congressional staff source said. But Ryan has consistently declined an interest in leadership. Some potential candidates may be waiting to see what Ryan ultimately decides before committing to a campaign.

Rep. Bill Flores, of Texas, said Thursday he expects the new speaker will be “somebody that hasn’t been talked about very much” in the weeks since Boehner said he would resign. Flores is chairman of the Republican Study Committee, a group that includes most House Republicans and that promotes conservative principles. Scalise was RSC chairman before Flores and that position served as a springboard for Scalise’s election as whip.

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