For nearly 100 years, the United States has been the guardian of peace in the world. Now, Donald Trump is threatening to withdraw—almost guaranteeing that chaos will worsen around the globe.  

Most irresponsibly, he has repeatedly suggested that Japan, South Korea and Saudi Arabia develop nuclear arsenals even though, as he told CNN , that nuclear proliferation is “maybe the biggest issue of our time.”  

He’s also declared the NATO alliance “obsolete”— a relic of the Cold War and an era when the U.S. was not “a poor country” — and threatened to pull U.S. forces out of Europe, Japan and Korea.  

Trump seems mindless of history. It was nearly 100 years ago — April 1, 1916, to be exact — when the U.S. entered World War I and saved Western Europe from German domination.  

The United States then reverted to “Trumpian” isolationism, only to have to fight another world war to avoid domination by Nazi Germany and Imperial Japan.  

NATO was created nearly 70 years ago as part of a multi-nation security structure that saved the world from domination by the Soviet Union and Communist China.  

In each case, the United States acted in its own national interest as well as that of its allies. Europe and Asia’s domination by unfriendly powers would have endangered U.S. national security.  

Now, if the full Trump doctrine takes hold, European countries — and the U.S., too — will be at the mercy of resurgent Russia. Vladimir Putin is trying to divide the West by bombing Syria and sending streams of refugees into Europe. Other times, he threatens to cut off natural gas to get his way and intimidates former Soviet bloc states that want to be part of the West.  

If the United States reduced its presence in Asia, allies including Japan, South Korea, and the Philippines — in addition to Taiwan and Vietnam — will be at the mercy of China, which is already claiming to own their territorial waters and is building up its military to assert the claims.  

And if the United States loses interest in the Middle East, countries like Saudi Arabia, Egypt and Jordan and the Gulf states will be menaced both by Iran and ISIS. Israel, the one ally Trump says he’ll stand by, will be utterly isolated.  

And if abandoned friends feel the need to go nuclear, the danger of atomic wars increases. (He should be offering to proliferate missile defense, not nukes.)  

In his scary interviews, Trump has implied that he wouldn’t casually abandon our allies—that he’s just employing shock-and-awe threats as leverage in deals to get the allies to pay more of the cost of U.S. defense.  

Asked by MSNBC’s Chris Matthews how he’ll get the allies to pay their “fair share” of defense, he said , “I’ll get it. I’ll get it. I’m the messenger.” He didn’t quarrel when Matthews suggested that his leverage was the threat, “we walk.”  

It’s true, United States allies do pay far less than we do as a percent of GDP on national defense. The United States spends 3.5 percent. The only NATO countries that meet the alliance’s goal of 2.0 are Britain (2.0) and Turkey (2.2). Germany and Belgium spend 1.0. Among other allies, South Korea spends 2.6 and Japan, 1.0. But Saudi Arabia devotes 10.8 percent to defense and buys much of its armament from the United States.  

Now, Donald Trump is a great deal-maker. Just ask him. But what he knows about is hotels, golf resorts and casinos.  

What he doesn’t know is foreign policy. In fact, he’s ignorant about it and often incoherent.  

He is making his strongest stand to muscle U.S. allies, not adversaries — just what he accuses Barrack Obama of, not without justification. He does say he’d use trade as geopolitical as well as economic leverage with China — a tall order — but says nothing about containing Russia.  

In his speech to the American Israel Public Affairs Committee, he clearly reversed himself on being “neutral” between Israel and the Palestinian Authority. He claimed he wouldn’t “pander” to the Jewish lobby like other politicians — then proceeded to do exactly that.  

He said his “number one priority would be “to dismantle the disastrous (nuclear) deal with Iran.” But then said “at the very least, we must hold Iran accountable by restructuring the terms” of the deal.  

He outrageously claimed “I’ve studied this issue in greater detail than anyone.” The audience started laughing, as though he knew the deal better than, say, Israel’s military. He responded, “Oh, yes. Oh. Yes.”  

The deal may be as disastrous as Trump claims, but renouncing it would permit Iran to resume its nuclear bomb program, now delayed for 10 years under the deal, and still keep the $100 billion in frozen assets the U.S. has already returned.  

Somehow, Trump promised, he’d “totally dismantle Iran’s global terror network”— operating on five continents — though he’s repeatedly said he wouldn’t put American boots on the ground.  

He clearly does not understand the advantages the United States gains from having foreign bases overseas. “We don’t benefit that much from NATO,” he said.  

But Europe was the base from which the U.S. deployed the forces that — as part of a broad international coalition — drove Iraqi forces from Kuwait in 1991.  

He told CNN “we have to wipe ISIS off the face of the earth, so fast and so violently, we have no choice.” He didn’t say how but would not rule out using tactical nuclear weapons to do so in order to not be “predictable.”  

He told CNN, “If I get in, our military will be bigger, better, stronger than ever before,” which means spending more on defense — he does not say how much.  

Currently, we spend $600 billion a year, of which keeping 200,000 service people abroad costs about $20 billion, according to Brookings Institution defense expert Michael O’Hanlon  

Trump’s approach to the Muslim world — barring most foreigners and having police monitor mosques — will make the world more dangerous, not less.  

All this — plus a possible global trade war triggered by threatened tariff hikes — will not make America great again. Quite the opposite.  

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