The transformation of the GOP into the party of Patrick J. Buchanan and Donald J. Trump—defined by cultural resentments, crude populism, and ethnic nationalism—is among the most important political stories of this century. But the GOP is hardly the only party that is undergoing some alarming tectonic shifts. Liberals wondering why conservatives who worry about Trump don’t join the Democrats should consider what is happening on their own side of the aisle.

If you want to understand just how radicalized the Democratic Party has become in recent years, look at the ascent of Senator Bernie Sanders of Vermont. A self-proclaimed socialist, Sanders served as mayor of Burlington, Vermont, and was then elected to the House in 1990 and the Senate in 2006. It’s hard to overstate just how left-wing Sanders’s views have been, at least by the standards of American politics.

Sanders has been a consistent defender of regimes led by anti-American dictators like Daniel Ortega and Fidel Castro. He took pains to separate his brand of socialism from the “totalitarianism” of the Soviet Union, but on a 1988 trip, repeatedly drew contrasts between the Soviet system and the United States that cast his own country in an unfavorable light. In the 1970s, Sanders called for the nationalization of entire industries and 100 percent taxation on those making more than $1 million. Since then, Sanders has moved away from calling for government to own the means of production, but he has hardly experienced a Damascus-road conversion. He is still a proud leftist.

For most of his career, Sanders—who identified as an independent but who caucused with Democrats—was treated like a curiosity and even a bit of a crazy uncle by Democrats, who considered the label socialist to be a smear.

No more.

The most prominent socialist in America, Sanders has gained a following, and in 2016, he challenged Hillary Clinton for the presidential nomination. He eventually lost, of course, but not before winning roughly 13 million votes and 23 primaries and caucuses against Hillary Clinton, who got 17 million votes and won 34 contests. He electrified Democratic audiences in ways she could not, drawing a crowd of nearly 30,000 in Portland. The hashtag “Feel the Bern” exploded in popularity in 2016. Sanders particularly inspired the younger generation, drawing far more votes in the primaries from those under the age of 30 than did Clinton and Trump combined.

The 77-year-old Sanders is now a front-runner for the 2020 Democratic nomination, with The New York Times declaring that his leftist ideas on health care, taxes, the environment, and other matters are defining the race.

“Those ideas that we talked about here in Iowa four years ago that seemed so radical at the time, remember that?” Sanders said during a return trip to the state earlier this month. “Shock of all shocks, those very same ideas are now supported not only by Democratic candidates for president but by Democratic candidates all across the board, from school board on up.”

“In 2016 Iowa helped begin the political revolution,” he continued. “Now as we move to 2020 our job is to complete that revolution.”

He’s not kidding, and he’s not alone. Among the freshman class of House Democrats, Alexandria Ocasio-Cortez—now the second-most-famous democratic socialist in America—is the unquestioned star among the base. According to Dan Balz of The Washington Post, Ocasio-Cortez is “the titular leader of a progressive grass-roots movement pushing the party to the left.” (The mere mention of her name elicits spontaneous applause on programs like The Late Show With Stephen Colbert.)

Another prominent member of the freshman class of House Democrats, Ilhan Omar, recently dismissed former President Barack Obama—who not that long ago defined the progressive wing of the Democratic Party—as too right-wing. “We don’t want anybody to get away with murder because they are polished,” she said, “we want to recognize the actual policies that are behind the pretty face and the smile.”

To more fully grasp the leftward lurch of the Democratic Party, it’s useful to run through some of the ideas that are now being seriously talked about and embraced by leading members of the party—ideas that together would be fiscally ruinous, invest massive and unwarranted trust in central planners, and weaken America’s security.

• The Green New Deal, a 10-year effort to eliminate fossil fuels “as much as is technologically feasible” that would completely transform the American economy, put the federal government in partial or complete control over large sectors, and retrofit every building in America. It would change the way we travel and eat, switch the entire electrical grid to renewable energy sources, and for good measure “guarantee” high-paying jobs, affordable housing, and universal health care. It would be astronomically costly and constitute by far the greatest centralization of power in American history.
• Medicare for all, which would greatly expand the federal role in health care. Some versions would wipe out the health-insurance industry and do away with employer-sponsored health plans that now cover roughly 175 millionAmericans. This would be hugely disruptive and unpopular (70 percent of Americans are happy with their coverage), and would exacerbate the worst efficiencies of an already highly inefficient program.
• Make college tuition-free and debt-free, with the no-debt promise including both tuition and living expenses—a highly expensive undertaking ($50 billion a year or so just for the federal government)—that would transfer money from less wealthy families whose children do not attend college to wealthier families whose children do. It could also have potentially devastating effects on many private, not-for-profit colleges.
• Increase the top marginal tax rate to 70 percent from its current rate of 37 percent for those making more than $10 million, unwise in the 21st-century economy and far above the average top rate for OECD nations; and impose a “wealth tax” that would levy a 2 percent annual tax on a household’s assets—including stocks, real estate, and retirement funds—above $50 million. It isn’t even clear whether a tax on wealth rather than income would be constitutional, but that almost seems beside the point.
• Abolish the U.S. Immigration and Customs Enforcement (ICE), which upholds immigration laws; protect “sanctuary cities” (local jurisdictions that don’t fully cooperate with federal efforts to find and deport unauthorized immigrants); and take down existing walls on the southern border, walls which Speaker Nancy Pelosi has referred to as “an immorality.” These policies signal that Democrats don’t really believe in border security and are mostly untroubled by illegal immigration.
• Eliminate the Senate filibuster, pack the courts, and put an end to the Electoral College. The effect of these would be to weaken protections against abuses of majority power.
• Reparations for African Americans to provide compensation for past injustices like slavery, Jim Crow laws, and redlining. (Senator Elizabeth Warren believes Native Americans should be included as well.) Reparations would pose countless practical problems and create unintended consequences, as David Frum argued in these pages.
• Opposition to any limits on even third-trimester abortions, and opposition to the Born-Alive Abortion Survivors Protection Act, legislation clarifying that babies who survive attempted abortions must receive medical care. Abortion is a very difficult issue that requires empathy on all sides—but for many of us, this stance of Democrats is morally incomprehensible.
• Increasing antipathy aimed at Israel, one of the most estimable nations in the world. Two freshmen Democrats, Representatives Ilhan Omar and Rashida Tlaib, have embraced the boycott, divestment, and sanctions movement targeting Israel, and House Democratic leaders faced a fierce backlash in their efforts to condemn the anti-Semitic remarks by Omar, who has a record of anti-Semitic comments and who most recently accusedsupporters of Israel of dual loyalties. (The Democratic House, unable to pass a measure that focused solely on anti-Semitism, eventually passed a resolution condemning “hateful expressions of intolerance.”)

To be sure, these views are not embraced by all Democrats—but they are ideas that are gaining adherents, including among several presidential candidates, and are fundamentally reshaping and radicalizing the Democratic Party. On every front, the Democratic Party is moving left, and the power of the left can be seen in the fact that even Democrats who oppose some of these policies are wary of attacking them. When it comes to challenging the progressive wing, Democratic candidates act as if they are walking on eggshells. (There will be no Bill Clinton–style Sister Souljah moment in the Democratic Party in 2020.)

If former Vice President Joe Biden enters the race, he will likely spend a fair amount of time apologizing for positions he embraced, like his tough-on-crime stance, his view that the Supreme Court went “too far” on abortion rights, and how he handled the Anita Hill accusations against Clarence Thomas when he was chairman of the Judiciary Committee. Biden has already said, “I’m told I get criticized by the new left. I have the most progressive record of anybody running for the—anybody who would run. Of anybody who would run.”

This embrace of radical progressivism and its colossal price tag is almost certainly going to hurt Democrats politically—most of their gains in 2018 were in suburban districts, among voters who tend to recoil at radicalism of any kind—and it could be politically disastrous. (Ocasio-Cortez enthusiastically embraced the label radical, saying, “It only has ever been radicals that have changed this country.”)

But beyond the electoral ramifications of the radicalization of the Democratic Party is what conservatives like myself consider to be its destructive animating philosophy. The trend is toward growing hostility to free markets and capitalism, in many cases to the point of barely contained contempt for it and for the wealthy. (When former Governor John Hickenlooper, a successful businessman and one of the more moderate candidates in the Democratic field, was asked by MSNBC’s Joe Scarborough if he would say he’s a capitalist, he repeatedly ducked the question. Beto O’Rourke, while declaring himself a capitalist, added, “Having said that, it is clearly an imperfect, unfair, unjust, and racist capitalist economy.”)

Many progressives champion the centralization of government power and collectivism, extreme egalitarianism, and a secularism that can bleed into intolerance toward people and institutions who hold traditional religious views on sexual morality.

The Democratic Party is embracing a form of identity politics in which gender, race, and ethnicity become definitional, and a belief in a common culture, unifying ideals, and the need for assimilation is weakened or shattered. (“I acknowledge the truth of the criticism that I have enjoyed white privilege,” O’Rourke recently said.) The Democratic Party is more and more unable to stand up to anti-Semitism. And it seeks “the elevation of human autonomy above other humane values,” as Michael Gerson has argued. The roots of this ideology are not in the labor movement so much as in the postmodern academy. The mood of many progressive Democrats these days is uncompromising and unforgiving.

Democrats want to focus their attention on the flaws and corruptions of Donald Trump, and they have a lot to work with. But you won’t become a saint through other people’s sins, Anton Chekhov said, and the Democratic Party will not become a responsible governing party because of the faults of President Trump.

Progressivism is wrecking the Democratic Party even as crude populism and ethnic nationalism have (for now) wrecked the Republican Party. Both are salvageable and both are worth saving, but that will require individuals who have identified with each party to fight to reclaim them; to show wisdom, decency, and courage in an age of extremism and intemperance.

Peter Wehner, a senior fellow at the Ethics and Public Policy Center, served in the last three Republican administrations and is a contributing editor at The Atlantic and a contributing opinion writer for the New York Times.