It was the soundbite heard 'round Capitol Hill: House Majority Leader and presumptive House speaker nominee Rep. Kevin McCarthy, R-Calif., has dropped out of the race for speaker. The Washington Post's Elise Viebeck explains the sudden news — and what happens next. (Julie Percha/The Washington Post)

Less than a year after a sweeping electoral triumph, Republicans are on the verge of ceasing to function as a national political party.

The most powerful and crippling force at work in the ­once-hierarchical GOP is anger, directed as much at its own leaders as anywhere else.

First, a contingent of several dozen conservative House members effectively forced Speaker John A. Boehner (Ohio) to resign rather than face a possibly losing battle to hold on to his job. Now they have claimed House Majority Leader Kevin McCarthy (Calif.), who had been considered the favorite to replace Boehner until he announced Thursday that he is dropping out of the race.

With no obvious replacement for Boehner in sight, “it is total confusion — a banana republic,” said Rep. Peter T. King (R-N.Y.). “Any plan, anything you anticipate — who knows what’ll happen? People are crying, they don’t have any idea how this will unfold, at all.”

Republicans including Rep. Darrell Issa (R-Calif). and Rep. Jason Chaffetz (R-Utah) - who is running for House speaker - say what it means that Rep. Kevin McCarthy (R-Calif.) is no longer seeking his party's nomination. (AP/C-SPAN)

Parallel currents of rage and chaos have been roiling the 2016 presidential race, diminishing hopes that an eventual nominee can bring order and direction to the increasingly dysfunctional party.

Initially, GOP elders believed that their primary would be a showcase for a cast of ­well-regarded senators and governors, current and former. They were confident it would be an appealing contrast to the quirky group of GOP candidates who had run in 2012, and to the Democratic contest, where Hillary Rodham Clinton appeared to be cruising to the nomination.

But government experience has become a liability for Republicans, rather than a credential. Celebrity billionaire Donald Trump, the leader in every poll, has rallied the conservative base by mocking the entire GOP establishment as weak and feckless. Many of the other candidates have followed his lead.

“You know Kevin McCarthy is out, you know that, right?” Trump crowed to a crowd of about 1,500 in Las Vegas, “They’re giving me a lot of credit for that, because I said you really need somebody very, very tough — and very smart.”

Former Arkansas governor Mike Huckabee, a presidential contender at the back of the pack, added in a statement blasted out by e-mail: “The race for Speaker of the House is not about Kevin McCarthy, it’s about burning the corrupt Washington political machine to the ground and rebuilding our country.”

The forces that have made the House ungovernable are coming from the same wellspring of insurgency, beginning with the tea party movement, that propelled the Republicans back into control of Congress.

In the House, Republicans regained and expanded their majority by picking up 63 seats in the 2010 midterm elections and 13 more last year. They now have their largest majority since the late 1920s.

After dropping out of the race for speaker of the House, Rep. Kevin McCarthy (R-Calif). said he did not want to be a "distraction" from the committee investigating the attack on Americans in Benghazi. (AP)

Battalions of conservative ground troops have come to Capitol Hill in the past five years with expectations that were not in line with what could actually be achieved while there is still a Democrat in the White House.

Disappointed in their ability to follow through on their campaign promises to turn back President Obama’s policies, they trained their fire on their own commanders.

For all their gains on the state and local level, Republicans are deepening the problems that have cost them the popular vote in all but one of the last six presidential elections. The divisive and exclusionary rhetoric of their 2016 contenders has hit a chord with primary voters — Trump, for instance, has made a series of insulting comments about women and immigrants — but threatens to further alienate key groups of voters in an increasingly diverse country.

Their contempt for compromise has also undermined the Republicans’ drive to prove that they can actually govern.

“This hell-no caucus — the degree of purity that they’re looking for doesn’t exist,” said former Senate Republican leader Trent Lott (Miss.), who was also once part of the House GOP leadership. “I’m sure they’re nice people, but Washington is not a place where you can come in off the street and make it work.”

In his announcement that he was abandoning his bid for the House’s top job, McCarthy said that it was time for a “fresh face.”

Had he become speaker, however, McCarthy would have been the first since 1891 to get the job with less than a decade of experience in Congress. Just five years ago, McCarthy co-wrote a book called “Young Guns: A New Generation of Conservative Leaders.”

Another of the book’s three authors was McCarthy’s predecessor as majority leader, Rep. Eric Cantor (Va.), whose surprising defeat in a Republican primary last year was an early warning of the problems ahead for party leaders in the House.

“It is imperative that we fight for what we believe in. But we should fight smartly. I have never heard of a football team that won by throwing only Hail Mary passes, yet that is what is being demanded of Republican leaders today,” Cantor wrote in a Sept. 25 op-ed in the New York Times, shortly after Boehner announced his resignation.

There are institutional forces at work as well that make it more difficult for the party to bring itself into anything resembling a formation.

Junior members of Congress no longer have to seek the favor of more senior ones to rise through the ranks. Modern media has given them the power to play to a national audience — as presidential contender and first-term senator Ted Cruz (R-Tex.) has demonstrated in the Senate.

In July, Cruz went so far as to call Majority Leader Mitch McConnell (R-Ky.) a liar on the floor of the Senate. Such a breach of decorum would have been unthinkable in earlier times, but it has burnished Cruz’s image with the conservative base.

Changes in campaign finance laws have made the parties themselves less powerful, and ideologically driven outside groups more so.

In the presidential race, the Republican National Committee set up a process aimed at making the nomination more orderly than in 2012 by compressing the calendar of state primaries and caucuses and allowing fewer debates.

That strategy may have backfired. Given the size of the Republican field — 14 candidates at the latest count — the new party-imposed order may actually have made it more difficult for any of the more mainstream candidates to overtake outsiders Trump, retired neurosurgeon Ben Carson and former Hewlett-Packard chief executive Carly Fiorina.

At the Obama White House, officials were not gloating at the Republican turmoil — in part, because it could pose problems for carrying out their own agenda. For instance, the president is going to have to rely on a large number of GOP votes to pass a Pacific Rim free-trade deal that is drawing opposition from Obama’s own party. Among those who are expressing resistance is Clinton, despite the fact that she had promoted such a deal when she was secretary of state.

“Republicans have to make some decisions about how to lead their conference,” said White House press secretary Josh Earnest. “Certainly it’s easy to poke fun at the chaos, but the fact is the challenge that is facing the next Republican speaker of the House, regardless of who it is, is the same challenge that John Boehner faced, the same challenge that Kevin McCarthy would have had to face — it is to unite a divided Republican caucus.”

“If the challenge wasn’t previously clear,” Earnest added, “it is today.”

Robert Costa contributed to this report.