At the Ronald Reagan Presidential Library in California last week, Republican Senator Tom Cotton of Arkansas engaged in some political bait-and-switch.

A potential 2024 presidential candidate, Cotton delivered a speech as part of the library’s “A Time for Choosing” series, in which high-profile Republicans were asked to address “the future of the conservative movement and the Republican Party.” He let it be known that he intended to argue that Ronald Rea­gan and Don­ald Trump were cut from the same cloth — an ambitious theme that generated a fair amount of advance buzz.

He couldn’t pull it off.

Cotton told his audience that those who believe the GOP must choose between following Reagan’s legacy or Trump’s are wrong. “For all their differences in temperament and style,” he said, “there’s a deeper continuity in the beliefs of our 40th and 45th presidents.”

But you can’t square a circle, and Cotton didn’t really try. He declined to “sketch out the similarities with great details about policies and programs.” Instead, he said, he would prove his point with reference to a painting: Both Reagan and Trump “adorned the walls of their Oval Office” with a portrait of Andrew Jackson.

From that unconvincing beginning, Cotton went on to make an unconvincing case that Reagan and Trump were, at bottom, champions of Jacksonian democracy, a political tradition “concerned first and foremost with protecting normal Americans and advancing their interests.”

It is fair to say that the Jacksonian tradition lives on in today’s Republican Party. The historian Walter Russell Mead characterizes the Jacksonian outlook as one “suspicious of untrammeled federal power,” “skeptical about the prospects for domestic and foreign do-gooding,” “opposed to federal taxes,” and “obstinately fond of federal programs seen as primarily helping the middle class .” Jacksonians are more likely to join the National Rifle Association and to be hawkish in wartime, says Mead; less likely to be represented among media and academic elites.

Cotton’s contention that this is the natural political home of “normal Americans” is of a piece with the way political analyst Michael Barone defines the Republican Party’s historical constituency: They are “people who are regarded by themselves and others as typical Americans, but who are not by themselves a majority of the electorate.”

But this applies to the Republican disposition generally. It doesn’t come close to bearing out Cotton’s claim of a “deeper continuity” between Reagan and Trump specifically, let alone his assertion that the future of the party can be simultaneously Reaganesque and Trumpian.

Trump was — is — the antithesis of so much that Reagan stood for.

The Gipper was a man of grace, civility, and dignity — the opposite of Trump, who has always confused bluster with strength and bragging with confidence. Reagan was widely read, deeply informed, and persuasive in sharing his views. (Anyone who doubts it should read the published collection of his writings, which shows a mind constantly at work.) It was during the Reagan ascendancy that the late Daniel Patrick Moynihan announced, with a touch of surprise: “Of a sudden, the GOP has become a party of ideas.” Trump, by contrast, neither reads nor thinks, and the party he dominates is not associated with either thoughtfulness or innovation. In 2020, the Trumpified GOP didn’t even bother to produce a platform; instead it boiled its views down to a single principle: “The RNC enthusiastically supports President Trump … and will continue to enthusiastically support the President’s America-first agenda.”

What is salient in politics changes from era to era, of course. Many policies that exemplified Reaganism in the 1980s would have no application to the Trump era, and vice versa. But changing circumstances cannot paper over the profound differences between the two men.

Take foreign policy. Reagan was the president who implemented a strategy to win the Cold War and deployed all his rhetorical power to weaken the moral standing of the Soviet Union. Trump was the president who repeatedly gushed over the world’s worst dictators, including Kim Jong Un, Xi Jinping, and Vladimir Putin. It is fatuous to pretend that there is no choice to be made between the legacy of the Republican who saw America’s enemies headed for “the ash-heap of history” and the Republican who praises the “genius” and “savvy” of Vladimir Putin for his invasion of Ukraine.

Or take immigration, the domestic policy area that perhaps more than any other epitomized Trump’s priorities.

In his Reagan Library speech, Cotton issued a fully Trumpian message on immigration. “The level of immigration — legal and illegal — has been too high for too long,” he declared. He called on Republicans to end most family-based immigration, to “finish the wall” on the Mexico border, and to “turn off the jobs magnet” that attracts so many economic migrants. Under no circumstances, he said, should there be an amnesty for unauthorized immigrants already in the country, not even in exchange for more border security.

This is light-years from the approach of Reagan, who endorsed open immigration as a candidate for the White House, and reiterated that view right up through his farewell address to the nation. “I believe in the idea of amnesty for those who have put down roots and lived here, even though some time back they may have entered illegally,” Reagan said in 1984. Two years later he signed legislation that enabled nearly 3 million aliens living in the United States to become legal permanent residents.

If Cotton wishes to make the case that the GOP’s best bet for growth lies in upholding the Trump template, he is surely free to do so. But to claim that Republicans can do that while still wearing the Reagan mantle is delusional.

For anyone concerned about where the Republican Party is headed, maybe the most compelling difference between Reagan and Trump comes down to numbers.

When Reagan was president, he was enormously popular with young voters, 61 percent of whom voted for him when he ran for reelection. During the Trump years, on the other hand, voters under 30 overwhelmingly disliked the president and 60 percent of them voted against him in 2020. By lopsided margins, new voters in Reagan’s day registered as Republicans; by equally lopsided margins, new voters during the Trump administration declined to register as Republican.

There is no joint Reagan/Trump path forward for the GOP. If Republicans stick with Trump — with or without Andrew Jackson’s painting — they must leave Reagan’s vision behind.

(Jeff Jacoby is a columnist for The Boston Globe).