The modern Republican Party, to the extent it considers anything to be important other than abject fidelity to Donald Trump, certainly does not consider history — its own or the world’s — as cause of any need for reflection or care.

The astonishing statement last week that Trump would welcome Russian attacks on our NATO allies is the latest indication that the man — and his party — are not merely ignorant of history but also unable to grasp the strategic importance of an alliance that has been at the absolute center of American foreign and military policy since Nazi Germany was beaten into submission in 1945.

“No, I would not protect you,” Trump claims he told a European leader while president. “In fact, I would encourage (Russia) to do whatever the hell they want. You’ve got to pay. You got to pay your bills.”

Setting aside that this exchange almost certainly never happened and is a fiction of Trump’s muddled brain, the stupidity of saying he would green light more of Vladimir Putin’s aggression in Europe by abrogating the U.S. commitment to NATO’s collective security model is simply unbelievable. Unbelievable until you consider the source.

First, NATO does not “pay” its bills to the United States. European allies commit to defense spending targets — some succeed, others don’t — on the theory that a unified front against a malevolent Russian dictator is better than every country fending for itself. Trump doesn’t understand this essential fact or, more likely, simply is a Putin patsy.

Here is some Republican Party history. In 1950, Dwight Eisenhower became the first supreme commander of NATO, a perfect alignment of experience and gravitas that allowed the American general who had engineered victory over the Nazis to head a multinational alliance designed to thwart any future Russian ambitions in western Europe. In taking the job — Eisenhower took a leave of absence from his job as president of Columbia University — Ike said, “In all history, this is the first time that an allied headquarters has been set up in peace, to preserve the peace and not to wage war.”

A bedrock feature of the alliance is Article 5 of the NATO charter, which identifies an attack on any member of the alliance to be an attack on all. A Russian attack on a Baltic nation or Poland, as Putin must surely dream about, means a conflict with the entire alliance. It’s called deterrence and it works. Article 5 has been invoked only once in NATO’s history, after the 9/11 attacks on the U.S.

Yet, this kind of solidarity and security is what the almost certain Republican presidential nominee is keen on destroying.

Nearly four decades after Eisenhower helped establish NATO, Ronald Reagan, in the final year of his presidency, stressed the importance of the alliance.

“The Atlantic alliance is the core of America’s foreign policy and of America’s own security,” Reagan said in 1988. “Preservation of a peaceful, free and democratic Europe is essential to the preservation of a peaceful, free and democratic United States.”

Reagan offered the essential description of what is at stake with Trump’s unhinged threats to NATO, not to mention his clear reluctance to fund the defense of Ukraine.

And since there are no coincidences in politics, that truism explains, at least in part, why the pro-Russian, Trump-advancing former Fox News mouthpiece Tucker Carlson was in Moscow interviewing Putin at the precise time Trump decided to go all in on trashing NATO.

During Carlson’s interview with Putin, the former KGB agent mixed conspiracy theories with blatant lies and made it clear he’s for peace so long as he gains control over Ukraine. The white nationalist wing of the GOP, that faction increasingly in control of what was once the party of Eisenhower and Reagan, lapped it up like so much Kremlin propaganda served cold to the MAGA base.

Putin is even more skilled at the Big Lie than his pupil, Trump. In Putin’s world, Poland started World War II by provoking Adolf Hitler. He uses that historic fiction to justify invading Ukraine.

“Mixing truth with complete falsehoods has been the Kremlin’s propaganda strategy for decades,” said the Russian opposition figure Mikhail Khodorkovsky. “It’s what made the invasion of Ukraine possible.”

And where amid this regression to pre-World War II American isolationism are the GOP’s foreign policy elites, the people with foreign policy experience or at least standing? It’s clear they got nothing beyond banal acquiescence to their “great leader.”

Most passed off the Trump threat with a shrug or, like House Speaker Mike Johnson, refused to comment. But Trump isn’t bluffing, as his former national security adviser, John Bolton, confirms. “People say, ‘Well, he’s not really serious. He’s negotiating with NATO.’ Look, I was there when he almost withdrew, and he’s not negotiating — because his goal here is not to strengthen NATO; it’s to lay the groundwork to get out.”

Sen. James Risch, the Idaho Republican who is the ranking member of the Foreign Relations Committee, has been invisible during his party’s divide over aid to America’s democratic allies. Risch, to his credit, voted for the final Ukraine aid legislation, but he is silent about the party’s anti-NATO standard bearer and, like his party, Risch embraced the ridiculous linkage between a border security proposal and assistance to embattled Ukraine. Trump killed the border proposal, of course, which Republicans insisted on having before deciding they like chaos better than a bipartisan compromise. The likely future of Ukraine now rests in the fever swamp of the barely Republican-controlled House, the place all sane ideas go to die.

And don’t forget that a majority of Senate Republicans rejected the Ukraine aid package, including stunning examples of political gymnastics by Trump toadies like Lindsay Graham and Marco Rubio. The party of Eisenhower and Reagan is now the party of an apologist for authoritarians who, if returned to power, will certainly blow up the totality of U.S. post-war security.

“Everyone should be scared as hell,” Sen. Chris Van Hollen, the Maryland Democrat, said. “Anybody who cares about American leadership, anyone who cares about protecting democracy, anybody who wants to take on authoritarians around the world should be scared to death by the fact that Donald Trump is telling us that if he was reelected president, he would throw our NATO allies to (Vladimir) Putin.”

The Atlantic writer David Frum resurrected an apt quote this week when he recalled the introduction to Allen Drury’s great 1959 novel, “Advise and Consent,” about a fictional Senate made up by the likes of Risch, Graham and Rubio.

“The fate of our country is not determined by the outcome of elections,” Drury wrote, “but by the dedication and character of those we entrust with power.”

The Republican Party’s willingness to trash NATO and give Putin Ukraine is our own Munich moment. We can stop Putin now or reap the consequences because there will be consequences.

Johnson, of Manzanita, Ore., served as chief of staff to the late former Idaho Gov. Cecil D. Andrus. His new book on the U.S. Senate in the 1960s — “Mansfield and Dirksen: Bipartisan Giants of the Senate” — has been published by the University of Oklahoma Press.