When Harriet M. Hageman announced her 2022 primary challenge against Representative Liz Cheney of Wyoming, House Republican leaders quickly endorsed her bid to oust a colleague whose condemnations of former President Donald J. Trump had made her a pariah in her own party.
But one member of leadership remained notably silent: Representative Steve Scalise of Louisiana, the No. 2 Republican. He viewed backing Ms. Hageman as a violation of what he calls his 11th Commandment, borrowed from President Ronald Reagan: “Thou shalt not speak ill of another Republican.” He waited until Ms. Hageman had defeated Ms. Cheney to throw his support behind her.
Mr. Scalise, a longtime rival to former Speaker Kevin McCarthy, is now mounting his own bid for the post. He has pitched himself as the man uniquely positioned to unite Republicans at a moment when they are deeply divided and demoralized after Mr. McCarthy’s historic ouster last week.
“We’re so divided; he can unite this Congress,” Representative Lance Gooden of Texas said of Mr. Scalise.
His candidacy is the culmination of a steady political climb for a deeply conservative Republican who once described himself, according to a local columnist, as “like David Duke without the baggage.”
In Louisiana, Mr. Scalise represents the First Congressional District, a place where the fossil fuel industry is king, and where conservatism is rooted in the myth of rugged individualism — and, at least in some quarters, a politics of racial resentment. It is where Mr. Duke, the former Ku Klux Klan leader, was elected to the State Legislature in 1989.
Mr. Scalise has suggested that his life and political career have been influenced by those forces. He made the remark comparing himself to Mr. Duke to Stephanie Grace, now a columnist for The Times-Picayune/New Orleans Advocate newspaper, when she first met Mr. Scalise in the 1990s. She wrote that Mr. Scalise’s point “was that the actual governmental philosophy Duke espoused isn’t far off from what was becoming mainstream conservative thought, what with its suspicion of taxes, set-asides and safety net programs such as welfare.”
(Over the weekend, Ms. Grace endorsed Mr. Scalise for speaker.)
Decades later, those views are as powerful as ever in the Republican Party as Mr. Scalise faces off for the speakership against Representative Jim Jordan of Ohio, a founder of the ultraconservative House Freedom Caucus.
Mr. Scalise is making the run despite having been diagnosed only weeks ago with blood cancer, for which he has been undergoing treatment. His supporters insist it has not diminished his capacity for the job.
A key plank of Mr. Scalise’s pitch to his colleagues is that he is a fund-raising powerhouse, second only to Mr. McCarthy. He has raised nearly $170 million over the course of his congressional career to help Republicans win elections. In the 2022 midterm elections, Mr. Scalise spent 112 days on the road campaigning for members and candidates. Over the past five years, his office said, he has given $7.2 million directly to Republican members and candidates and transferred $50 million to the National Republican Campaign Committee.
“Kevin McCarthy was fabulous at raising the resources our conference needed,” said Representative Ann Wagner of Missouri. “The only person second to that is Steve Scalise.” Ms. Wagner, a longtime ally of Mr. Scalise, said she had accompanied him on fund-raising swings in which he visited more than a dozen districts in three days.
Over the past year, Mr. Scalise has been marginalized by Mr. McCarthy, who has privately described him to colleagues as ineffective, checked out and reluctant to take positions, and cut him out of all major decision making.
The dynamic was frustrating for Mr. Scalise at the time. But now, his allies believe that the fact that he was not involved in the debt ceiling negotiations with President Biden, which ultimately proved to be a catalyst for Mr. McCarthy’s downfall, could make him a viable option for the hard-right members who rebelled against the former speaker.
While most far-right Republicans are expected to back Mr. Jordan on Tuesday when they are scheduled to choose a nominee for speaker, Mr. Scalise is imploring them to support him as a second choice. Under the current rules of the Republican conference, whoever receives a majority in that secret-ballot vote will be the party’s nominee when the full House meets to elect a new speaker, now expected on Wednesday.
Lawmakers allied with Mr. Jordan are trying to raise that threshold to unanimity, which would put Mr. Scalise at a disadvantage. For now, however, Mr. Scalise has been telling right-wing lawmakers that while he wishes he could be their first choice, he hopes that if he emerges as the nominee, they will at least vote for him on the floor.
His pitch to other Republicans is more straightforward. Mr. Jordan, who has been endorsed for the speakership by Mr. Trump, would have a more difficult time helping vulnerable Republicans win in districts President Biden won in 2020, especially when Mr. Jordan supported primary opponents for 12 sitting members of Congress.
Mr. Scalise arrived on Capitol Hill in 2008, after winning a special election to replace Representative Bobby Jindal, who was elected governor.
A political animal since childhood, he came to Washington wanting to be a part of everything: He joined the Bible study group and the congressional baseball team, where he would play in a Louisiana State University baseball jersey and buy tickets for all of his staff members and their kids. He pushed for a seat on the Energy and Commerce Committee, where he became a strong ally of the oil and gas industry. And he quickly rose to become the recruitment chair of the National Republican Campaign Committee and then chairman of the Republican Study Committee, then the largest group of conservative House Republicans.
Mr. Scalise, the first person in his family to graduate from college, grew up in Jefferson Parish, in the suburbs just outside of New Orleans, a region where the population ballooned in the latter half of the last century as white residents fled the desegregating city. Born into a family of Sicilian immigrants, Mr. Scalise used to tell staff members stories about how his ancestors worked in the sugar fields in Garyville, La.
His rise in Washington was rapid. By 2014, he had ascended to the No. 3 position in the House. Then a blogger broke the story that as a state legislator in 2002, Mr. Scalise had spoken at a meeting of a white nationalist group founded by Mr. Duke, a revelation that threatened to derail his political career.
Under intense pressure from Democrats to step down, Mr. Scalise said the speech was a “mistake I regret,” claiming he did not realize what the group was when he accepted the invitation. At the time, he received a significant nod of support from his old friend Cedric Richmond, then a congressman from New Orleans, who is Black.
“I don’t think Steve Scalise has a racist bone in his body,” Mr. Richmond said then. (Mr. Richmond could not be reached for comment about Mr. Scalise’s run for the speakership.)
In 2020, Mr. Scalise voted to remove Confederate statues from the U.S. Capitol, breaking with a majority of his party, including Mr. Jordan.
Still, Mr. Scalise most often sides with Republicans. He pushed hard for the passage of legislation in 2015 that resulted in the repeal of a 40-year ban on oil exports, handing the oil industry a huge victory. He also played a major role in 2017 in muscling through Republicans’ $1.5 trillion tax cut law, which primarily benefited big corporations, multimillionaires and other wealthy individuals. A supporter of Mr. Trump, he voted to overturn the 2020 election results and for months afterward steadfastly promoted the lie that the election had been stolen.
In 2017, Mr. Scalise was gravely wounded when a gunman, distraught over Mr. Trump’s election, opened fire on members of the Republican congressional baseball team at a practice. The bullet tore up his internal organs, shattered bones and caused major internal bleeding, leaving Mr. Scalise in critical condition.
He had to undergo multiple surgeries and months of work at an inpatient rehabilitation center to relearn how to walk. He returned to the Capitol three months later, walking gingerly with two canes.
“I’m definitely a living example that miracles really do happen,” he said at the time. Today, Mr. Scalise appears almost fully healed. With the help of a shoe with a lifted sole, his gait is now normal.
In August, Mr. Scalise announced that he had been diagnosed with a rare form of blood cancer but planned to return to Washington to continue working as he underwent several months of treatment.
Colleagues said that part of his pitch to them over the past few days was that the treatment was going better than his doctors had anticipated and he was in shape to do the job.
“They have changed his treatment and shortened into a three-month period of time, down from six,” said Ms. Wagner, a close friend. Both Mr. Scalise’s wife, Jennifer, and his doctors, she added, “have agreed that he’s more than healthy enough for this challenge.”
It is not clear precisely what toll his illness and treatment have taken on Mr. Scalise. He has taken to wearing a heavy-duty mask at news conferences and on the House floor, a striking change for a Republican who eschewed a face covering as the coronavirus pandemic raged, once calling federal mask mandates “Democrats’ masking political theater.”
Richard Fausset contributed reporting from Atlanta.