With so much attention focused on the changes at the top of the Democratic ticket, we are not paying enough attention to the lack of change at the top of the Republican ticket. This month, Donald Trump won his party’s nomination for the third time in a row. Whatever we can say about him, he is a transformative figure.

This further confirmed, at least to me, the wisdom of my decision eight years ago to break with the Republican Party. In January 2016, I warned what then were my fellow republicans that if they nominated mr. Trump, he would pose a serious threat to the nation. But I added that there was another reason to oppose him: Mr. Trump’s nomination would pose a profound danger to the Republican Party, in ways that Hillary Clinton never could. “Because while Mrs. Clinton could inflict a defeat on the Republican Party, she could not redefine it,” i wrote. “But Mr. Trump, if he were the Republican nominee, it would.”

And so he has. Few people in American history have overhauled a political party as quickly and as fundamentally as Trump has. To understand how different it is, we need to briefly go back to how things were in the pre-Trump era.

During the time I served in three Republican administrations (Reagan and both Bushes), the party was hawkish and unrelentingly critical of the Soviet Union and then Russia. It was a support for NATO. It condemned anti-American dictators and authoritarian leaders. It was deeply committed to “the common task of strengthening democracy throughout the world,” like Reagan said 1982. And it argued that it was in America’s interest to provide global leadership.

The Republican Party advocated free trade and fiscal discipline, although in practice it often failed. It was welcoming of legal immigrants and refugees. Republicans argued that reforming entitlement programs was essential. Many of its leading figures insisted that moral character was an essential quality for political leaders and especially for presidents. Republicans also warned that a cruel, mean-spirited political culture was undermining a decent society.

Today, the Republican Party has abandoned each of these commitments.

Even in the case of abortion, things have changed. The Republican Party has been pro-life for decades, including in its party platform. But this month, that plank was removed. Princeton’s Robert P. George, a major figure in the pro-life movement, pointed out that that plank has been replaced by the claim that abortion policy is entirely the business of the state, which can, if they choose, allow abortion up to birth. Mr. Trump succeeded in overturning Roe v. Wade, but now that the abortion issue is a political liability, he has thrown “the pro-life cause under the bus,” Mr. George wrote on Facebook. Mr Trump has succeeded where liberal Republicans have long failed.

So how are we to understand what it means to be a Republican now?

Jonathan Rauch, a scholar at the Brookings Institution and my sometime co-author, told me that to begin to understand what has happened, you have to understand the difference between a personal political machine and a traditional political machine. Unlike normally functioning parties and their political machines, such as Tammany Hall, Rauch said, a personal political machine is dedicated to the interests of an individual and that individual’s family, loyalists and agents. It accepts only one person as a leader and demands submission to that person. Today, Trump is that person.

Personal machines differ from party machines, Rauch added, because they are incompatible with democratic politics. Even a corrupt party machine maintains institutional interests separate from those of its leaders. It rewards and punishes behavior based on the party’s electoral interests, prioritizing winning elections over personal loyalty to the boss. A party machine thus rewards supporters by getting them elected and then keeping them in office. In contrast, a personal machine is willing to lose elections rather than share power with other leaders or factions. It puts the leader before the party, and it would rather the party lose an election than the leader lose control.

“Because a personal machine puts loyalty before electability, it must resort to authoritarian and anti-democratic measures such as coercion and intimidation to maintain its grip on the party,” Rauch said. “It can physically threaten those who don’t play ball. And it will use propaganda and party organization to build up the leader as the only true expression of the party. That’s why Trump’s Republican Party is a cult of personality.”

Yuval Levin of the American Enterprise Institute told me that the Republican Party should effectively be perceived as an anti-left party. “It understands itself defensively, as speaking for a coalition that is abused, excluded, mistreated and pushed around by a left-leaning elite in American life,” he said. “Its sense of purpose is therefore fundamentally defensive. This means that it is largely defined in opposition to its understanding of the left, more than it is defined by a specific political vision of its own.”

“That opposition,” he added, “obviously gives shape to some assertive or constructive action as well, but the vision of America that underlies that action is largely a function of what Republicans believe Democrats are trying to destroy.” JD Vance, Mr. Trump’s pick for vice president, told American Conservative magazine 2021, “I think our people hate the right people.” (Mr. Trump’s choice of Sen. Vance, regardless of election wisdom, confirms the criticisms of both Mr. Rauch and Mr. Levin.)

This reactionary version of the party is drawn to Mr. Trump because he defines himself by his enemies, and those enemies are in many cases the left-wing elite. The left despises Mr. Trump, and since the Republican Party has implicitly become a party that stands for what the left despises, it has been very difficult to separate Republican voters from Mr. Trump in the name of some more positive vision or ideal. . Mr. Levin put it this way: “The left isn’t going to hate anybody more than they hate Mr. Trump, so the Republicans aren’t going to love anybody more than they love Mr. Trump.”

A third way to understand today’s Republican Party, something that becomes more apparent with each passing day, is that it has become a populist rather than a conservative party. That doesn’t mean it isn’t conservative here and there, now and then. What this means is that when traditionally conservative views are out of line with populist views, it is the traditionally conservative views that are most often discarded. The Republican Party’s move toward populism is not entirely new; even before Mr. Trump, the Republican Party was trying to become more of a labor party and reorient the party towards how people actually live their lives from day to day. Nor did the embrace of populism have to be all bad.

Populism has its place. It can be an understandable response to huge and rapid economic and social changes. It can alert elites to problems they may be out of touch with, including massive inequality, an indifference to beleaguered lives and fractured societies, and widespread institutional failures. As the political theorist Francis Fukuyama has written“Populism is a very crude expression of public will that does not like institutional constraints.”

Mr. Trump tapped into the growing resentment of millions of voters. He was seen by them as their tribune. Unfortunately, he exploited their fear and did next to nothing to solve their problems. But it doesn’t seem to matter to them. It’s all about the position.

The Republican Party, rather than embracing the best aspects of populism, has taken on its vices: anti-intellectualism, anti-institutionalism and anti-elitism; feeding off negative emotions such as anger, grievance and revenge; and a tendency to believe and spread conspiracy theories. Populism often looks for scapegoats and often blames immigrants and those who are ethnically and culturally different. Populists are also historically attracted to demagogues and authoritarian personalities.

But the most troubling trait that has defined the Republican Party in the Trump era is a relentless assault on reality, fused with lawlessness and an embrace of illiberalism.

The Republican Party once preached the importance of standing for moral truths and resisting moral relativism; today it is in important respects nihilistic. The Republican Party once described itself as the party of “law and order”; it now worships a man who is a criminal, who was found responsible for sexual assault and defamation, and who portrays the violent mob that attacked the Capitol as a bunch of patriotic “J6 martyrs.” Republicans once proudly proclaimed their reverence for the Constitution; in Milwaukee they crowned as their leader a man who tried to undermine it.

It is difficult and terrible to know that the political party to which I have devoted a significant part of my life has become the greatest political threat to the country I love.

Peter Wehner is a contributing opinion writer for The New York Times and a senior fellow at the Trinity Forum who served in the administrations of Presidents Ronald Reagan, George HW Bush, and George W. Bush. He is the author of “The Death of Politics: How to Heal Our Frayed Republic After Trump.” This article originally appeared in The New York Times.