One hundred seventeen foreign policy and legal experts have signed an open letter refusing to support Donald Trump. The letter criticizes Trump’s promise to kill the families of terrorists and to torture terrorism suspects if he is elected president.

The letter also warns that Trump’s “expansive view of how presidential power should be wielded against his detractors poses a distinct threat to civil liberty in the United States.”

Trump has promised to change libel laws to punish publication of “purposely negative stories.” He has also defended the dictator Vladimir Putin against charges of complicity in the murder of 34 Russian journalists.

Among those who signed the letter were Michael Chertoff and Michael Mukasey. Chertoff is the former director of the Department of Homeland Security and served as a judge on the U.S. Court of Appeals for the Third Circuit. Mukasey is a former U.S. attorney general who served for 18 years as a U.S. district court judge.

A week earlier, Gen. Michael Hayden, the former director of both the CIA and the National Security Agency, told HBO’s Bill Maher: “I would be incredibly concerned if a President Trump governed in a way that was consistent with the language that candidate Trump expressed during the campaign.” Hayden also suggested that military officers might refuse to follow unlawful orders given by a President Trump.

While Mukasey, Chertoff and Hayden may legitimately be criticized as hypocrites — having been serial violators of Americans’ civil liberties themselves — this certainly qualifies them as experts on the subject.

It could hardly have come as a surprise to Trump or his handlers that he would be asked the following question at last Thursday’s Fox News debate: “(W)hat would you do, as commander‐​in‐​chief, if the U.S. military refused to carry out those orders (to kill the families of terrorists and to torture terrorism suspects in violation of the Geneva Convention)?”

“They won’t refuse.” Trump shot back. “They’re not going to refuse me. Believe me.”

“But they’re illegal,” an incredulous Bret Baier said to Trump, referring to the unlawful orders.

Trump dug his hole deeper and, in doing so, his answer became a political Rorschach test:

“I’m a leader. I’m a leader. I’ve always been a leader. I’ve never had any problem leading people. If I say do it, they’re going to do it. That’s what leadership is all about.”

Baier had asked Donald Trump about his willingness to follow the rule of law, which is the bedrock of any constitutional democracy. But Trump’s answer reflected a stunning disconnect from this basic concept, focusing instead on his certitude that the illegal orders would be carried out. The legality of the underlying orders simply didn’t enter into the equation. It wasn’t a factor.

Trump’s primitive understanding of political leadership is rooted in the concept of Das Fuhrerprinzip; a German phrase that roughly translates as “The Leader Principle.” It is an autocratic legal philosophy that found its zenith in the totalitarian bureaucracy of the Nazi Third Reich.

Werner Best, the Gestapo’s legal adviser, explained Das Fuhrerprinzip in the 1940 edition of his book “Die Deutsche Polizei” (“The German Police”). According to Best, any form of pre‐​existing law “which governs the actions of the authorities is not regarded as law” since “(t)he will of the leaders, in whatever form … administers law” and therefore alters all valid law.

“As long as the police carries out the will of the leadership,” Best wrote, “it is acting legally.”

The day after the Fox News debate, Trump’s campaign quickly backtracked from his insistence that the military will follow his illegal orders. The campaign issued a written statement that possessed a logical coherence uncharacteristic of Trump’s typical verbalized thought process.

“I will not order a military officer to disobey the law,” the statement read. “It is clear that as president I will be bound by laws just like all Americans and I will meet those responsibilities.”

But just a day later Trump was at it again, making statements that he would follow the law, but would also seek to broaden, expand and open up those laws to allow him to do those things that are now illegal.

Many intelligent people discount any comparisons with the rise of the Nazi party in Germany. They argue that Donald Trump’s campaign promises are nothing more than pragmatic bluster that will be abandoned if he is elected president. Others argue that the U.S. is not Weimar Germany and that the checks and balances unique to our Constitution would prevent what happened in Germany from happening here.

Former U.S. Senator Jim Webb has said: “If you’re voting for Donald Trump, you may get something very good or very bad.” Which begs a question. Why gamble? Especially with something as important as the Bill of Rights?

Even highly educated people can have bad political instincts. “There is no reason for despair,” professor Albert Einstein told the press, when asked to comment on the Nazis’ 1930 electoral victories that gave them only 18 percent of the popular vote.

Less than three years later — after the Nazis obtained a solid plurality of over 30 percent of the vote — Einstein was in exile in Brussels when he renounced his German citizenship.