At a press conference Wednesday morning in his Wisconsin hometown, House Speaker Paul Ryan overflowed with praise for Donald Trump.

“He connected in ways with people that no one else did, he turned politics on its head,” Ryan told reporters. “Now he will lead a unified Republican Party.” Only weeks earlier, appalled by Trump’s coarse remarks about grabbing women, Ryan had refused to campaign with the Republican nominee. But after Trump’s stunning election triumph, Ryan brushed off such “intra-party issues” as unimportant. “This needs to be a time of redemption, not a time of recrimination,” he said.

Good luck with that.

Trump has never been one for turning the other cheek. “Always hit back against critics and adversaries, even if it looks bad,” he wrote in “The Art of the Deal.” His vindictive streak was on display throughout the presidential campaign, and prominent Trump advocates have repeatedly vowed payback for anyone who opposed them. “Mr. Trump has a long memory, and we’re keeping a list,” his surrogate Omarosa Manigault said on election night. Broadcaster Sean Hannity, accusing Trump’s conservative detractors of “sabotage,” let it be known that they would face a “day of reckoning” after the election. Ryan, declared Hannity, “is not going to be speaker of the House in January.”

Nov. 8 marked a stunning victory for the Republican Party, which has now won control of the White House, both houses of Congress, 34 governorships, and 68 of the nation’s 99 state legislative chambers. It was also a crushing repudiation of Barack Obama’s legacy and his leadership of the Democratic Party. Not since 1929 has the GOP so dominated political life in America.

But for conservatives, the new order is disturbing.

Trump is no conservative and never has been. The classic Reaganite principles of limited government, free markets, peace through strength, robust internationalism, American exceptionalism, and traditional social values have little resonance for the president-elect. His “vision thing,” to the extent he has one, is of a neo-isolationist populism. “Don’t forget, this is called the Republican Party,” Trump said last May. “It’s not called the Conservative Party.”

It was a fair point. Conservatives don’t own the Republican Party. At best, they have been its largest and most influential faction. Yet even in Ronald Reagan’s heyday, prominent Republicans rejected Reaganite values. As chairman of the Senate Finance Committee, for example, Bob Dole spent much of the 1980s opposing the Gipper’s supply-side economic reforms. The federal behemoth grew more swollen, not less, during Reagan’s years in office — and swelled still more under his successor, George H.W. Bush. Even William F. Buckley Jr. famously battled Reagan over his opposition to giving up the Panama Canal.

Yet while Republicans never really marched in lockstep to a conservative drummer, most of them came to see the GOP as the natural home for Reaganite values and the most reliable defender of conservative governance.

That will change under Trump. He is the new head of the Republican Party, and his influence will be felt throughout the ranks. Many on the right were dismayed by the stream of conservatives, both in and out of government, who set aside their philosophical objections and embraced Trump during the campaign. Now, as he prepares to move into the White House, that stream will become a torrent. In a page 1 subheadline on Thursday, The Wall Street Journal summarized the tectonic shift now underway: “Party members across the country move toward adopting positions held by the president-elect that they previously opposed.”

And for conservative Republicans who decline to cut their conscience to fit this year’s fashions? They won’t be in the wilderness, exactly, but political life for them is about to become more uncomfortable.

Some of Trump’s potential agenda items — replacing the Affordable Care Act, repudiating the Iran nuclear deal, filling the vacant Supreme Court seat with a Scalia-caliber judge, lowering the sky-high corporate income tax rate — movement conservatives will enthusiastically support. But much of what Trump campaigned on is anathema to them. If the incoming president is serious about killing the families of suspected terrorists, deporting millions of undocumented immigrants, weakening First Amendment protections for the press, cozying up to Vladimir Putin’s Russia, and imposing ruinous trade barriers, it will be incumbent on GOP conservatives to fight him.

The pull of partisan loyalty has always been hard for elected officials to resist. It has grown exponentially harder in our hyperpolarized environment — and the ascent of a new president with a vengeance reflex will make it harder still. Republican conservatives will need all the backbone they can muster when the leader of their party pushes them to support his anticonservative nostrums.

It would be wonderful if Trump, having captured the highest office in the land, resolves to abandon the smash-mouth style for which he is known and makes a point of listening to and learning from those who disagree with him. That would be a decided improvement over the last eight years of Obama’s my-way-or-the-highway superciliousness.

Hope springs eternal, but realists must assume that Trump will remain true to form. Which means it will take courage for Republicans — especially the committed conservatives among them — to oppose him when he’s wrong. That proved hard enough to do when Trump was merely the party’s nominee. It’s about to get a lot harder.

Jeff Jacoby is a columnist for The Boston Globe.