One of the great lessons of the 14th century Bubonic Plague was that rats make terrible pets.

Even as loathed vermin scurrying along sewer ditches and darkened corners inside people’s homes, rats — and the fleas they carried — proved capable of killing tens of millions of people around the globe. The havoc they wreaked dramatically altered the course of human history.

To be sure, rats are amazing, relentless, adaptable creatures. They are virtually un-killable. For every one you finally manage to execute, six more pop up in its place, each generation smarter and more efficient than the last.

Anyone who has waged war on rats cannot help but marvel at their ability to outsmart humans. It is only a matter of time before we find them driving city buses and running casinos in Las Vegas. Forget drones and droids. Rats will be our doom.

Even the great “Caddyshack” exterminator Carl Spackler would be no match for the modern rat.

Rats feed off of clutter, thrive in confusion, cherish mayhem and reign over chaos.

They are Masters of the Swamp.

For four years now, Democrats in Washington have lectured the country about the paramount importance of integrity in elections. We have been hectored over and over about the sanctity of every vote.

Today, these very same Democrats are desperately urging that the 2020 federal elections be conducted by the U.S. Postal Service.

Set aside the shoddy record the post office has at delivering mail and the fact that it has never conducted an election in history. Just look at the small part they have played in elections already. A month after New York’s Democratic primary, races have still not been settled — because of lost ballots that have been lost, stolen or mishandled.

Turns out, Democrats only care about election “interference” when they are peddling elaborate lies about how such mythical interference hurt them. Ever adaptable, Democrats quickly evolved from fretting over rigged elections to openly supporting widespread corruption of elections.

Or, take the rioting, looting and firebombing in American cities today.

What supposedly started as peaceful outrage over police treatment of Black citizens in America has been hijacked by anarchists hellbent on destroying the country.

As decent Americans of every political stripe watch in horror as the mayhem burns out of control, Washington Democrats move quickly to capitalize on the misery.

The riots are all President Trump’s fault, according to Democrats. And then it is his fault all over again when he dispatches federal resources to quell the violence that local politicians have proven incapable of managing.

But never do rats thrive more lustily than during a full-blown pandemic.

Nearly 150,000 Americans have already died in this once-in-a-century plague from China. The nation is truly at war against an invisible enemy.

In other words, this is the perfect time for Washington Democrats to pillage for their own personal political profit.

Mr. Trump, they say, was slow to address the pandemic. This, from the very vermin who paralyzed the federal government for the first two months of the pandemic in order to pursue a fraudulent impeachment trial against Mr. Trump.

When Mr. Trump shut down flights of Chinese nationals into the United States, these very same Democrats accused him of being racist, “xenophobic,” and urged citizens to gather — unmasked — in New York City’s Chinatown.

After all, there is no time like a plague when rats like to party it up.

• Charles Hurt is opinion editor of The Washington Times. He can be reached at churt@washingtontimes.com or @charleshurt on Twitter.