These days America sometimes looks as if it were slipping into the grip of another Red Scare. Only this time the object of fear and loathing is the far-right menace, not the far-left one.

The first Red Scare happened after the Bolshevik Revolution in 1917. The second followed WWII, and helped commence the Cold War.

Both scares involved a hysterical overreaction to a genuine threat. Totalitarian communism was antithetical to America's most cherished values, and anti-communism was the morally correct position to take.

Some took it too far. The overreaction led to loyalty oaths and star-chamber hearings before the House Un-American Activities Committee and Hollywood blacklists and a general atmosphere of what, today, we might call political correctness: an intolerance of dissenting ideas that challenged, or were insufficiently devoted to, the prevailing anti-communist orthodoxy. The more common name for the overreaction is McCarthyism.

All of this produced almost inevitable blowback, which came to be known as anti-anti-communism. Anti-anti-communists did not support communism, but they also opposed McCarthyism. To muddle the issue even further, many on the left were at least sympathetic to communism, and at least a few were objectively pro-Soviet, so it was easy to lump anti-anti-communists in with those who were pro-communist, and it could be difficult to navigate all of the finely grained distinctions.

Those debates have passed into history's sepia pages. Now the current debate over the alt-right has begun to display some of the same hallmarks.

To begin with, there is the undeniable existence of a clear and present danger. The racist right's identitarianism is antithetical to America's most cherished values, and opposing the alt-right is the morally correct position to take. The threat must be countered at every turn.

At the same time, the wholesome and necessary opposition to bigotry has started to metastasize into something less healthy.

You can see that in the way Berkeley reacted to a speech by Ben Shapiro. From the militarized police preparation to the emotional counseling for students, you'd have thought Shapiro, a Jewish conservative who opposes Donald Trump, was the reincarnation of Adolf Eichmann.

You can see it at the Oregon Bach Festival, which recently fired British conductor Matthew Halls for affecting a Southern accent while joking with a friend. The friend, Reginald Mobley, is from the South, and black. A woman reported Halls for making racist comments. Mobley insists "there was nothing racist or malicious" about his friend's joke. Too bad, festival officials said; Halls is out. Mobley told a British newspaper Halls "has been victimized and I'm very upset about it."

You can see it at the University of Iowa, which requires job applicants to promise they will "demonstrate their contribution to diversity and inclusion" if they are hired. (Virginia Tech tried to impose a similar litmus test for faculty members a few years ago.) To consider why that might be problematic, imagine the university were to demand that applicants "demonstrate their fidelity to capitalism and free enterprise."

You can see it in the proliferation of college "bias response teams," which swing into action when somebody reports somebody else—informs on them—for saying or doing something that might be viewed as offensive or hurtful. On today's campus, that can be practically anything. One actual case: "Anonymous student reported that African-American Alliance's student protest was making white students feel uncomfortable." Another resulted in the defunding of a student satirical newspaper after it poked fun at safe spaces.

You can see it in the debate over the Southern Poverty Law Center, which has come under fire for conflating mainstream conservatives, and even non-conservatives such as Ayaan Hirsi Ali, a fellow at the Harvard Kennedy School who opposes Islamic extremism, with neo-Nazis and Klansmen. As National Review put it last year, "A category … that includes both Aryan Brotherhood felons in San Quentin and Somali-Dutch atheist women with celebrated literary careers is not an especially useful category."

Like anti-communism in the 1950s, this atmosphere also has inspired blowback. The term for the current phenomenon is Trumpism. And, as with anti-anti-communism, the term covers a lot. It includes decent people who are tired of seeing other decent people fired for making innocent jokes. It also includes virulent bigots like the ones who turned out to commit mayhem in Charlottesville.

All analogies are inexact, and it's easy to push this one too far. The current situation differs from earlier Red Scares in a number of important respects—starting with the fact that for all the sympathy communism garnered in some circles in earlier decades, avowed communists never enjoyed electoral success (although a few socialists did). Bigots, however, have done extremely well in American politics until quite recently—and, arguably, still do.

Another difference: While the Red Scares permeated every sector of American society, most of the intolerant excesses of today's tolerance warriors are confined to colleges and universities.

All the same, history has a funny way of echoing itself. During the Cold War the far-left movement in the U.S. received clandestine support from the Kremlin—and vehemently denied it. Hmmmm. Who does that remind you of today?

This column originally appeared at the Richmond Times-Dispatch.