House Speaker Paul D. Ryan (R-Wis.) speaks Saturday at the 1st Congressional District Republican Party of Wisconsin's "Fall Fest" event in Elkhorn, Wis. (Anthony Wahl/AP)

Donald Trump trashed Ted Cruz’s wife and suggested his father was involved in John F. Kennedy’s assassination, but the senator from Texas still endorsed him. Trump mocked Marco Rubio’s cotton mouth and slight stature, but the senator from Florida still got in line. Trump turned Paul D. Ryan’s mentor and former running mate Mitt Romney into a personal whipping post, but the House speaker from Wisconsin still hopped aboard the Trump train.

These were not the only Republican luminaries to link arms with Trump. Wisconsin Gov. Scott Walker testified to his leadership strength. New Jersey Gov. Chris Christie and party chairman ­Reince Priebus, who once committed themselves to diversifying the GOP coalition, flew around on Trump’s luxury jet and defended his racially charged, nationalistic rhetoric. And the special guest celebrated by Sen. Joni Ernst (R-Iowa) at her “Hogs and Harleys” political festival? Yes, it was Trump.

Trump’s turbulent campaign, on display here at Sunday night’s second presidential debate with Democratic nominee Hillary Clinton, has damaged far more than his own White House prospects. It threatens to diminish an entire generation of Republican leaders who stood by him and excused his behavior after attacks against women, the disabled, Latino immigrants, Muslim Americans, Syrian refugees, prisoners of war, Gold Star parents and others.

“There is nobody who holds any position of responsibility who in private conversations views Donald Trump as equipped mentally, morally and intellectually to be the president of the United States,” said Steve Schmidt, a veteran GOP strategist. “But scores of Republican leaders have failed a fundamental test of moral courage and political leadership in not speaking truth to the American people about what is so obvious.”

In the wake of a new Washington Post report showing Republican presidential nominee Donald Trump speaking in very lewd terms about women in 2005, some Republicans are calling for Trump to step down as nominee. (Thomas Johnson/The Washington Post)

When this election season began nearly two years ago, Republicans were as excited as they had ever been by the diverse galaxy of stars that rose to prominence in the Obama era. Most of them hitched their wagons to Trump’s, out of loyalty to their party and fear of alienating his fervent supporters.

Although some withdrew their endorsements and disavowed Trump over the weekend after The Washington Post obtained video of Trump making lewd comments about sexual assault, they nevertheless are tainted by their associations with him. The question being asked Sunday was how long the stench would last.

“Everything Trump touches dies,” said Republican consultant Rick Wilson, who is advising independent candidate Evan McMullin.

John “Mac” Stipanovich, a GOP insider and lobbyist in Florida, said: “Most Republican officeholders gritted their teeth and endorsed and even embraced Donald Trump. . . . All of those people were collaborators, and all of those people will have to live with their collaboration for the rest of their political lives.”

A handful of Republicans resisted Trump throughout. Sens. Jeff Flake (Ariz.), Ben Sasse (Neb.) and Lindsey O. Graham (S.C.) spoke out loudly and consistently, as did Ohio Gov. John Kasich, who withstood pressure from Priebus to endorse Trump.

Romney, the party’s most recent presidential nominee, delivered a forceful and complete condemnation of Trump and his brand of politics during the primaries. And then there’s the Bush family. Jeb Bush, a former Florida governor, admonished Trump repeatedly in the primaries, while his father, former president George H.W. Bush, recently let it slip privately that he intended to vote for Clinton.

These were not the only Republicans warning against the political dangers posed by Trump.

“Since Day One, I have been waving these giant red flags in front of people saying, ‘No, no, no, don’t go down this road because this road leads to our party being very tainted and a candidate who’s dangerously unfit to be president,’ but people went storming ahead down that road anyhow,” said Katie Packer, a former Romney adviser who ran an anti-Trump super PAC in the primaries.

John Weaver, a longtime strategist and Kasich adviser, likened the situation to going back in time and offering Republican officeholders a ticket on the maiden voyage of the Titanic. “They bought the ticket knowing there wouldn’t be enough life rafts once the ship hit the iceberg,” Weaver said.

“We knew that no one who has gotten involved with Donald Trump in his personal life, in his professional life or in his political life has come out of that for the better. No one,” he added. “So why any of our aspiring political leaders thought that they could survive being associated with him and grow from that is beyond me.”

Wilson fears that the legacy of Trump’s campaign could haunt Republican candidates for many election cycles to come, just as Democrats in the 1980s and 1990s were hurt by their ties to former president Jimmy Carter and iconic liberals like Sen. Edward M. Kennedy (Mass.).

“This is going to last forever,” Wilson said. “For years now, Democrats will be able to roll out TV ads and say, ‘When John Smith says today he’s for a brighter future, remember who he stood by: Donald Trump. He stood by Donald Trump’s misogyny, racism, sexism and stupidity.’ ”

Schmidt warned that elected officials who “were scared and cautious about confronting this manifest disgrace to our national life will not be serious candidates for national office.”

“The Republican Party will look like Berlin circa 1945,” Schmidt said. “The wreckage will take a substantial amount of time to pick up. There will be a restoration, but it is going to require a monumental feat of leadership by someone who has not yet revealed themselves to the American people.”

That wreckage extends to older luminaries like former New York mayor Rudolph W. Giuliani, who sacrificed his reputation as “America’s mayor” — earned in the wake of the Sept. 11, 2001, terrorist attacks — to become, in the eyes of many fellow Republicans, a Trump toady.

Again and again, Giuliani rushed to Trump’s defense and punched back on his behalf, including on Sunday when he spoke on all five television public affairs shows as a substitute for Trump campaign manager Kellyanne Conway, Christie and Priebus, who backed out of their scheduled appearances.

Then there are the politicians who thought Trump could give them a leg up in their own careers. In Virginia, Corey Stewart, a county-level official with eyes on the governorship, appointed himself Trump’s “mini-me.” He gave fiery introductions at rallies across the commonwealth, and on Friday, he defended Trump’s bragging about groping women and aggressively pursuing sex with one who was married.

“He acted like a frat boy, as a lot of guys do,” Stewart said.

In Florida, Attorney General Pam Bondi, who also has ambitions for higher office, stepped forward during the primaries as one of Trump’s most loyal spokeswomen. But she got caught up in a Trump scandal over her political group’s acceptance of an undisclosed and unlawful $25,000 contribution from the Donald J. Trump Foundation and her office’s subsequent decision not to investigate alleged fraud at Trump University.

Stuart Stevens, a veteran strategist who helped run Romney’s 2012 campaign, said the Republican Party is in “a nightmare scenario.”

“Donald Trump has always been a ridiculous candidate for president, and the only thing that’s surprising is that it took this long for that ridiculousness to gel,” Stevens said. “It’s already hurt our country, it’s already hurt our politics. It’s just been a very destructive candidacy.”