This generation’s penchant for a moralizing brand of politics — in which opponents are not just wrong-headed but in fundamental ways wrong-hearted, even wicked — began on college campuses in the 1960s in arguments over Vietnam and whether one looked sympathetically or contemptuously at the blossoming counterculture.

Few imagined that different incarnations of these early arguments would continue into adulthood and now old age. 1990s politics were a morality play pitting Bill Clinton who won the White House promising to repeal a “decade of greed and self-seeking” in the Reagan-era 1980s, against Newt Gingrich and self-styled Republican revolutionaries, who sought to use Clinton’s sexual transgressions to drive him from office. Clinton, who in most moods tried to be a uniter, survived only by posing the divisive “which side are you on” question to advantage: Many more people were with him than Gingrich.

9/11 looked briefly like an event that would transcend political divisions and unite the country around shared conviction. Soon enough though, George W. Bush’s confrontational leadership style and decision to wage war not only in Afghanistan but Iraq meant that national security became one more subject to ask which side are you on. The combination of Bush’s wars and the 2008 financial meltdown were key prerequisites to Donald Trump’s later takeover of the GOP.

Above all, it was Trump’s insight that the convergence of social media and always-on mobile technology meant that incendiary language and vicious attacks on opponents could be more than an occasional tactic. Harnessed with abandon, it could be the basis for an entire grievance-based political movement.

Historically, political arguments — no matter how heated or even violent — were a means to resolving important substantive issues. Historian James G. Randall in 1940 termed the parade of failed leaders and Supreme Court justices in the 1840s and 1850s “the blundering generation,” whose alleged short-sightedness and grandstanding led to a violent Civil War. Most later historians rejected the characterization. There was no middle path or incremental remedy that was going to prevent a climactic conflict over slavery, the most important question of the country’s first century.

In today’s politics, by contrast, the argument itself, and the occasion to excoriate the opposition, often is more important than the substance of the argument. This is how Republicans can rally behind Trump on Iran or tariffs or the intersection of presidential decisions with family business interests, even as his policies diverge from their own past positions and they would no doubt bitterly denounce the exact same choices from a Democratic president.

This highlights several distinctive signatures of this generation’s politics.

First, they often revolve around questions of values and virtue. That’s a different emphasis than the previous generation’s arguments, which were more typically about material things. If one person thinks marginal tax rates should be 40 percent, and another thinks they should be 30 percent, they might fight passionately but in the end it’s pretty easy to compromise at 35. In 1990 by contrast, Gingrich anticipated Trumpian politics by 25 years when he co-authored a famous memo urging Republicans to cast their opponents with such language as “sick,” “traitors,” “bizarre,” “corrupt,” and “pathetic.” Hillary Rodham Clinton usually didn’t talk this way in public, but there was the famous episode when she revealed at a fund-raiser she thought was private her view that half of Trump supporters belonged to a “basket of deplorables” with racist or sexist views. The language of the culture wars leaves little for opponents to say to one another.