The opinions expressed by columnists are their own and do not necessarily represent the views of Townhall.com.

All my life, I have known this rule about people: Those who don't fight the greatest evils will fight lesser evils or make-believe evils.

This happens to be the morally defining characteristic of the left. During the Cold War, many liberals and nearly all conservatives fought communism, but the left fought anti-communism. The left opposed American military buildups and regarded the Cold War between America and the Soviet Union as nothing more than two scorpions in a bottle fighting to the death. They loathed Presidents Nixon and Reagan, not Communist Party Secretary-General Brezhnev.

They regarded Reagan's labeling of the Soviet Union as an "evil empire" with contempt. Typical was the reaction of one of America's best-known intellectuals, Henry Steele Commager, then a professor of history at the Amherst College. He said, "It was the worst presidential speech in American history, and I've read them all."

With regard to fighting communism -- which, aside from Nazism, has been the greatest evil in the modern world (it killed and enslaved far more people than Nazism) -- the left was an obstacle, not an ally. The left in the West and elsewhere did far more to enable communist evil than to stop it.

The same holds true with regard to the greatest evil in the world at this time: totalitarian Islam, or Islamism. The left is doing precisely what it did during the war against communism: It's fighting the anti-Islamists, not the Islamists. Just as it labeled anti-communists "cold warriors" and other derisive epithets, the left labels those fighting Islamism as "Islamophobes" and, of course, "racists." In the moral order as perceived by the left, it is the anti-Islamists who are the enemy of the good.

In this battle, the left fights American conservatives -- and Israel, the country in the front line against Islamism. In a nutshell, rather than fighting evil, the left fights those who fight evil.

Therefore, if you have moral clarity, you are not on the left. If you have moral clarity, you can be a liberal, a conservative, a centrist, an atheist, a believer, a Christian, a Jew, a Muslim, a Buddhist, a Hindu, a black, a white, a Latino, an Asian, a Native American, a gay, a straight or a bisexual. But you cannot be a leftist.

The problem, however, is that people want to feel morally good about themselves, and no one wants this more than the left. It has written the proverbial book on moral self-esteem. Therefore, it does not merely believe that it is morally superior to all others; it knows it is. Leftists know they are more compassionate, more enlightened, more intellectual and more intelligent than conservatives. And they know that they care more about the "downtrodden," the "marginalized" and the "disenfranchised" than conservatives.

But to feel good about yourself, you have to fight against something bad. Since the left doesn't fight real evil (that would take moral courage in addition to moral clarity), it has to fight lesser evils or made-up evils.

For example, the left relentlessly fights racism in America, even though America is the least racist multiracial society in history; it relentlessly fights sexism in America, the country that has afforded unprecedented equality and liberty to women (but it does not fight the terrible sexism that pervades the world's most women-suppressing societies -- those in the Muslim world); and, of course, it fights Nazis and white supremacists -- who, though evil, constitute an utterly negligible threat to America today. Fighting Nazis in Germany between 1933 and 1945 was an act of moral heroism. Given their negligible numbers and nonexistent power, fighting Nazis in America in 2017 is an act of moral onanism.

There's a lot more on the list of made-up or lesser evils that the left fights instead of fighting real evil. It fights religious Americans, specifically religious Christians and especially evangelicals. Now that's an enemy worth fighting -- those mean Christians (and Jews) on the religious right. And it fights conservatives, or at least the conservatives who fight them.

And, of course, it fights global warming. Leftists have convinced themselves that the real fight against evil in the world today is not against Islamism; it's against carbon emissions.

And now, we can add statues to the list. The left was AWOL against communism, and it's AWOL against Islamism. But it's in the vanguard of fighting statues.