Donald Trump’s conservative critics have one last hope: defeat. If Republicans suffer humiliating defeats in the midterm elections, they suggest, President Trump will get the blame. Influential donors and grass-roots Republicans will turn on him, and the party will get back to normal. Not so long ago this was the party of Paul Ryan and free trade. This was the party of George W. Bush and compassionate conservatism. This was a party whose self-performed autopsy after the 2012 election called for more minority outreach. After Mr. Trump, why can’t the Republicans be that party again?

The ranks of anti-Trump Republicans grow thinner by the day. They’re retiring from Congress. They’re writing memoirs blasting their former friends. But they hold out hope for the future. If the Republican Party could undergo such a profound change in personality and policy thanks to just one man in a mere three years, who’s to say it can’t change back? The Trump coalition seems so impermanent, after all, a motley mix of Southern evangelicals, businessmen who think like the Chamber of Commerce and disaffected white voters from the Rust Belt. Throw in foreign-policy hawks and anti-interventionist America Firsters, and Mr. Trump’s Republican Party looks like an impossible contradiction. It can’t last. Can it?

Yes, it can. In fact, the party that President Trump has remade in his image is arguably less divided and in a better position to keep winning the White House than it has been at any time since the 1980s. What Mr. Trump has done is to rediscover the formula that made the landslide Republican Electoral College victories of the Nixon and Reagan years possible. Mr. Trump’s signature themes of economic nationalism and immigration restriction are only 21st-century updates to the issues that brought the Republican Party triumph in all but one of the six presidential elections between 1968 and 1988.

Some of the parallels are obvious. President Trump talks about crime and left-wing agitation in much the same way that Richard Nixon once did — and Ronald Reagan, too, especially during his time as governor of California. Mr. Trump’s combination of force with an aversion to large-scale military interventions and nation-building also bears a resemblance to the policies of Republican presidents past. Dwight Eisenhower and Mr. Reagan also preferred to build up military strength without engaging in the kinds of prolonged wars for which Lyndon Johnson and George W. Bush are remembered. And while Mr. Nixon was mired in Vietnam, he ran as a candidate eager to find an exit.