The three-week battle to choose a House speaker may be over, yet the fallout for the United States and its reputation as a sound government and a beacon of democracy will be long-lasting and profound.The Republicans in the House unanimously voted for a man who made it his mission to try to overturn the 2020 presidential election, who put the political whims and needs of former President Donald Trump ahead of the interests and will of the American people. A party that once cared deeply about America as the leader of the free world, and believed in the strength, dependability and bipartisan consensus that such a role required, has largely given way to a party now devoted to an extremism that is an active threat to liberal values and American stability.Americans and the world are starting to get to know Mike Johnson, now the second in line to the presidency, and it’s a troubling introduction. Donald Trump may not be in the White House, but Trumpism as an institution has transcended the man and provided the operating principles for the House of Representatives and much of the Republican Party.Those operating principles include allowing Mr. Trump to all but select the speaker, and elevating, in Mr. Johnson, one of the party’s most prominent election deniers. It has been disturbing to watch the slide from Republican speakers like Paul Ryan and John Boehner, who denounced attempts to challenge the election results, to the hemming-and-hawing of Kevin McCarthy, to the full-blown anti-democratic stands of Mr. Johnson. And it has certainly been a long slide from the party of Ronald Reagan — whose 11th Commandment was not speaking ill of other Republicans and who envisioned the party as a big tent — to the extremism, purity tests and chaos of the House Republican conference this year.Every Republican present in the chamber voted on Wednesday for Mr. Johnson, reflecting the exhaustion of a party that has been ridiculed for incoherence since it deposed Mr. McCarthy for working with Democrats to fulfill the basic function of Congress, to fund the federal government. The choice of Mr. Johnson came after Mr. Trump helped engineer the result by torpedoing a more moderate candidate, setting the stage for the 2024 presidential election to unfold with someone in the speaker’s chair who has proved his willingness to go great lengths to overturn a free and fair vote.It’s obvious why the former president was so supportive of the new speaker. Mr. Johnson was “the most important architect of the Electoral College objections” to Mr. Trump’s loss in 2020, as a New York Times investigation found last year. He made unfounded arguments questioning the constitutionality of state voting rules, he agreed with Mr. Trump that the election was “rigged,” cast doubt on voting machines, and supported a host of other baseless and unconstitutional theories that ultimately led to a violent insurrection at the Capitol on Jan. 6, 2021.Mr. Johnson now refuses to talk about his leading role in that shameful drama. When a reporter for ABC News tried to ask him about it on Tuesday night, he would not respond; his fellow Republicans booed the question, and one yelled at the reporter to “shut up.” Such questions cannot be dismissed when Mr. Trump is the leading candidate for the Republican presidential nomination. Though changes in the law and Democratic control of the Senate make it much harder for the House of Representatives to impede certification of the vote, the American public deserves a speaker of the House who will uphold the will of the people, not someone willing to bend the rules of an election for his own side.More immediately, while his election as speaker will make it possible for the House to continue functioning, it is not clear that Mr. Johnson is committed to the work of actually governing. At the end of September, he voted against the stopgap spending measure negotiated by Mr. McCarthy that prevented a government shutdown. That bill was an important litmus test; Mr. McCarthy brought it to a vote and got it passed with bipartisan support, over the objections of Mr. Trump, leading to his downfall as speaker. Two other Republican speaker candidates, Tom Emmer and Steve Scalise, also voted for it — and were also vetoed by the extreme right.Mr. Johnson now says he would support another temporary stopgap to give the House time to pass drastic spending cuts. That promise may have won over the Republicans who blocked the candidacy of another extremist, Jim Jordan, last week. But Mr. Johnson’s voting record so far leaves little doubt that he prefers the performance of taking positions to actual lawmaking.This leaves Congress in a precarious state. The 22 days of indecision, backbiting and bullying that followed Mr. McCarthy’s ouster did significant damage to the reputation of the United States as a country that knows how to govern itself. One of the country’s two major political parties sent a piercing signal to the world and the nation that it is no longer a reliable custodian of the legislative branch — and many party members knew it.“This is junior-high stuff,” Representative Steve Womack, Republican of Arkansas, said a few days ago. “We get wrapped around the axle of a lot of nonsensical things. But, yes, the world is burning around us. We’re fiddling; we don’t have a strategy.”Nevertheless, Mr. Womack voted for Mr. Johnson. His preferred choice was Mr. Emmer, a Republican whose views are more moderate and who might have led the party out of its hard-line cul-de-sac. Mr. Emmer had the support of many other Republicans, but his candidacy never even got to the House floor for a vote.That’s because Mr. Trump exacted retribution for Mr. Emmer’s willingness to recognize the true outcome of the 2020 election. Mr. Emmer voted to certify those results, defying Mr. Trump, and the former president has never forgiven him. On Tuesday, he denounced Mr. Emmer on social media as a “globalist” and a fake Republican who never respected the MAGA movement. After Mr. Emmer dropped out in the face of growing opposition from the far right, Mr. Trump boasted to a friend: “I killed him.”Mr. Johnson will take control of the House at a moment when the United States needs to demonstrate leadership on the world stage. One of the most important decisions is coming right up: Will Mr. Johnson support Mr. Biden’s request for nearly $106 billion for aid to Ukraine and Israel? He has already voted against most bills to support Ukraine’s fight against Russian aggression.As speaker of the House, he plays a crucial role in the legislative system, determining the agenda by choosing which bills will reach the House floor for a vote, supervising committee appointments, and hammering out compromises to get legislation passed. (Nancy Pelosi, for example, demonstrated make-or-break leadership in creating the Affordable Care Act.)Mr. Johnson believes that the “true existential threat to the country” is immigration and led the Republican Study Committee, the largest group of conservatives in the House, which issued a plan to erode the Affordable Care Act, Medicare and Medicaid. It also refers to free public education as “socialist-inspired.”On social issues, Mr. Johnson has also embraced the positions of the hard right. He supported state laws that criminalized gay sex, and wrote in 2004 that gay marriage would “place our entire democratic system in jeopardy” and lead to people marrying their pets. As a congressman, he celebrated the demise of Roe v. Wade in 2022.It bears repeating that this Trump loyalist is now second in line to the presidency. The former president has never accepted being out of the White House, and it’s clear he still commands firm control over half of the Capitol building.Source photograph by Brendan Hoffman/Getty Images.The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram. More