He was born in the 1940s but still shows plenty of energy and a distinct New York brashness and humor while debating fellow candidates or taking questions from voters or reporters. His supporters sometimes seem frustrated, even angry, that government hasn’t done what they think our elected officials were sent to Washington to do, that politicians don’t pay attention to the will of the people and haven’t enacted — or even really tried to enact — policies aimed at making America the best it can be. And he often seems just as angry.

He laps up criticism of his positions as compliments, and his devotees take them that way, too, aiming for an “outsider” president not bound by convention and not beholden to the “establishment.” His supporters are so fed up with the status quo that they barely care about their man’s poorly defined policies. Instead they are enthralled with his populist promises of ensuring that Americans are no longer taken advantage of economically, with particular venom reserved for free trade and hedge fund managers.

And all of this has him doing far better than many pundits, including admittedly your humble columnist, ever anticipated, such as holding a nearly 20-point lead over his nearest competitor in New Hampshire and leaving the establishment wondering what just hit them. In Iowa, a once-unlikely victory seems in reach, especially if he can increase turnout among parts of the electorate who historically haven’t made much effort to caucus.

I speak, of course, of Bernie Sanders, the self-described socialist whose early success and the enthusiasm of whose supporters is surprising even veteran watchers of presidential campaigns. But if you took the above description as a profile of the leading Republican candidate, Donald J. Trump, you would also be correct.

That Messrs. Trump and Sanders have so much in common should particularly discomfit Republicans and conservatives. One similarity, which has more often been found in European politics, is particularly frightening.

That similarity is a trait which is inherent in Progressives — and all the more so in socialists — but which is disappointing and perhaps frightening when found among wide swaths of Republican-supporting voters in the United States: Authoritarianism, which one Internet source defines as “favoring or enforcing strict obedience to authority, especially that of the government, at the expense of personal freedom.”

As Matthew MacWilliams noted in a most insightful article in Politico recently, that trait explains why Donald Trump’s performance exceeds what anybody would have predicted using commonly analyzed voter characteristics such as age, income, race or education (even though much of The Donald’s support comes from those without college educations.)

MacWilliams describes his survey of 1,800 voters across the country and his finding that authoritarianism is the “single statistically significant variable (that) predicts whether a voter supports Trump.” Although the method is not of his creation, how he classified who is authoritarian is clever given that few Americans would describe themselves that way: He asked four questions about child rearing:

Is it more important “to have a child who is respectful or independent; obedient or self-reliant; well-behaved or considerate; and well-mannered or curious?” As you may have guessed, “respondents who pick the first option in each of these questions are strongly authoritarian.”

My own answer to each question was the second option. Perhaps that explains in a roundabout way why my distaste for Donald Trump runs so deep.

Before delving further into Mr. Trump, allow me to briefly dispense with Bernie Sanders and his supporters when it comes to authoritarianism:

Government is force. Approximately everything you do at the command of government is done only because they have the guns and the jails. While there are legitimate functions of government, the debate over which occurs both inter-party and intra-party, one thing is certain: the larger the government, the more obedience to authority is required of the citizenry.

Since Bernie Sanders is calling for the largest, most expensive, most intrusive government ever dreamed up by a leading major party candidate during my lifetime, his supporters are necessarily the most authoritarian gang in the nation. No aspect of a Sanders platform could occur without millions of federal government guns prepared to be pointed at millions of American citizens.

Of course, the dreadlocked college students, aging hippies, and other idealistic naïfs who “feel the Bern” see themselves as champions of the little guy, fighting the power, sticking it to the man, and so on. These cheerleaders for what FDR might have called “freedom from want” are utterly blind — as they must be to maintain their views — to the fact that they propose to create “freedom” and “equality” for some by enslaving nearly all in the cheerful bondage of good intentions.

No, Virginia, there is no authoritarian quite like the oh-so-caring Uncle Bernie and the grinning throngs of evil’s softest faces which surround him in college towns across the country.

Now back to Mr. Trump: He is going to “make Mexico pay for a wall.” He is going to “beat” China and Japan and Mexico and every other country we trade with. He is going to deport eleven million illegal immigrants but expeditiously let back in those he thinks are the “good ones.” Like a vengeful prosecutor, he’s going to stop “the hedge fund guys (from) getting away with murder.” He’s going to make sure America is “respected” by its enemies and allies alike.

Trump’s rhetoric sounds like nothing as much as a mid-level mafia boss (although Andrew McCarthy makes a fair case that Trump sounds like a sharia practitioner.)

Mr. Trump is going to lay down the law, to Americans and Mexicans, to Europe and Asia, to Vladimir Putin and Ayatollah Khamenei, and his supporters are slurping it up.

It is understandable that after more than seven years of a spineless America-last Obama administration, voters might pine for a resurgent America proudly reclaiming its place as the world’s sole superpower.

At this point I make a plea to my fellow citizens who do indeed feel this way and who currently support Mr. Trump: Please reconsider whether he is the proper vessel through which to channel your righteous anger and frustration.

Braggadocio and bombast do not equate to “peace through strength,” much less to “speak softly and carry a big stick.” Foreign adversaries know it. Most Americans, in our hearts, know it too. And the better your sense of history, the more the political madding crowd should frighten you.

It’s not just that Mr. Trump is a life-long liberal pretending to be a conservative, a man who supports increased government involvement in health care and still defends the Supreme Court’s reprehensible Kelo decision. Any one of these should be disqualifying for a Republican candidate.

No, it’s not just what he believes. It is how he wants to enforce his beliefs. Other than the occasional mention of “making deals” to “get things done” — which I thought was exactly what conservatives are furious about when it comes to current Republican politicians — it’s that he intends to impose his vision through the force of his will alone, as if he were the CEO, president, and chairman of the board of a company named Trump Nation. It is the most explicitly authoritarian approach to government I have ever seen in a leading candidate of either major party.

As history has proven repeatedly, authoritarians are destined to feel the vengeance of the many they wrong, but not before they cause much strife and suffering.

Is this what you want the nation to go through, as it undoubtedly will if Mr. Trump is president?

Tyrannical leaders such as Sanders or Trump are authoritarian not because they believe that America needs leadership but because they believe that Americans need to be led.

Our Founders would recognize supporters of this mindset as Tories, not as descendants of the most important revolution in the history of humankind and of the men who pledged “our Lives, our Fortunes and our sacred Honor” to secure it.

Donald Trump so far from what American conservatism, much less libertarianism, represents, so far from what “life, liberty and the pursuit of happiness” is supposed to mean, so far from what I want my children to understand the United States of America to be, and so near to mob rule, that even if mine were the deciding vote, I will not vote for Donald Trump in the presidential election.

And so, my friends who currently back Trump, I hope you will reconsider your support for a man who, not least as a political “blank slate” on which you are drawing your own chalk figure of a politician, has more in common with Barack Obama than he has with Ronald Reagan.