Donald Trump just lobbed a grenade into the normally staid world of European-American diplomacy, using a joint interview with two of Europe’s biggest newspapers to call NATO “obsolete,” predict that the European Union would fall apart and announce that the US wouldn’t really care if it did, and threaten to potentially start a trade war with Germany over BMW’s plans to build a manufacturing plant in Mexico.

For good measure, Trump also criticized German Chancellor Angela Merkel, one of Washington’s closest allies, while hinting that he’d be willing to lift the sanctions imposed on Russian President Vladimir Putin, who has rattled many in Europe by annexing Ukraine’s Crimean Peninsula and threatening to use force against other of his neighbors.

Merkel, Trump said, had made a "catastrophic" mistake by allowing more than a million refugees into her country, a decision that has seriously dented her popularity at home. The president-elect also said hinted that he’d be willing to remove the sanctions on Russia if Putin agreed to reduce his nuclear stockpile (which is almost literally the opposite of what the Russian leader has been talking about).

"They have sanctions against Russia — let's see if we can strike a few good deals with Russia,” Trump said in the joint interview. “I think there should be less nuclear weapons and they have to be reduced significantly, that's part of it.”

The remarks forced Secretary of State John Kerry to spend one of his last days as America’s top diplomat repairing the damage that Trump has done before even taking the oath of office. In an interview with CNN, Kerry said it was "inappropriate" for Trump to "be stepping in to the politics of other countries in a quite direct manner."

Kerry is right to be worried. Bashing NATO and the European Union, and alienating Germany, is a plan for tearing apart US relations with the EU — for weakening the agreements that underpin America’s status as the world’s sole superpower and that maintain peace on the European continent.

It also means that Trump is talking about radically reshaping US foreign policy in a way that would significantly boost Putin’s influence while leaving America’s allies scrambling to figure out where they stand and how much they can trust in the future stability of an international system that has brought unprecedented economic strength and stability to the continent for decades.

“What Trump proposes is [American] geopolitical suicide,” Daniel Nexon, a professor at Georgetown University who studies great power politics, writes at the Lawyers, Guns, and Money blog. “Make no mistake: you should be very worried right now.”

The allied West — and how Trump is already weakening it

After World War II, the United States and its allies attempted to create a new world — one defined by rules and order, in which such a devastating war could never happen again.

A Western alliance, NATO, was designed to deter Soviet aggression. International institutions, like the United Nations, were set up to allow countries to resolve differences peacefully. Global financial institutions, like the General Agreement on Trade and Tariffs (which would become the World Trade Organization), were designed to prevent countries from reimposing the self-defeating trade barriers that made the Great Depression far worse than it had to be.

For the past 70 years, these institutions have worked astonishingly well. In his joint interview with the Times of London and German’s Bild newspaper, Trump basically takes aim at all three pillars of those systems: military, political, and economic.

Start with NATO. In the interview, Trump reiterated his claim, first made during the campaign, that NATO was obsolete because it didn’t pay enough attention to terrorism and because other members didn’t pay enough to fund it. He claimed that he’d been proven right.

“I took such heat, when I said NATO was obsolete,” Trump says. “And then they started saying Trump is right.”

That’s not when European leaders have been saying in the immediate aftermath of Trump’s speech. Speaking to reporters in Brussels before a meeting of top EU diplomats, German Foreign Minister Frank-Walter Steinmeier said the comments had caused "astonishment and agitation" within the military alliance.

That’s because NATO works through commitment: Members pledge that an attack on one will be treated as an attack on all. As Trump calls the value of the alliance into question, other states might question whether he would actually defend a NATO ally if attacked — especially since, during the campaign, he said he might not. If countries don’t believe in that promise, then it stops serving as a deterrent — potentially encouraging Russia to menace a NATO member state.

“The United States president-elect is actively working to increase the risk of military escalation and war in Europe,” Thomas Rid, a professor at King’s College London’s Department of War Studies, tweeted in response to the interview.

Trump would be perfectly happy if the EU crumbled

That’s the military component, the first leg of the world order’s tripod. Trump’s comments on the European Union — one of the cornerstone international institutions of the postwar order — are even more startling. Trump actively predicted that the EU would fall apart, and suggested that the US wouldn’t really care if it did.

“The EU was formed, partially, to beat the United States on trade, OK?” he asked rhetorically. “I don’t really care whether it’s separate or together.”

Here you see Trump’s basic mindset at work — the world is a series of zero-sum trade-offs. If the EU serves European countries well, economically, then it must be bad for the United States. Hence he won’t try, as President Obama has, to use US influence to prevent more countries from leaving the European Union.

Trump’s view is wrong on the economics. But perhaps more scarily, it’s ignorant of the politics.

See, the European Union was designed as much more than a free trading bloc. Its architects designed it, very explicitly, as a way of unifying Europe politically. The closer Europeans are economically, and the more a sense of a shared European identity there is, the less likely that France and Germany, say, are to see each other as military threats.

This, in fact, has worked. Europe is what scholars Barry Buzan and Ole Waever call a "security community," a place where countries "stop treating each other as security problems and start behaving as friends." That is directly tied to European integration, which established a set of postwar institutions that make international disputes more like normal politics. The Europeans take their problems to each other and their shared institutions, such as the European Commission and Parliament.

Because they spent the immediate postwar years forcing themselves to take to those institutions, Europeans proved that they can work, and thus made them far more appealing options than conflict. Europeans' fundamental beliefs about how European states should treat each other has transformed with the EU's institutions.

After the Euro and refugee crises, the rise of anti-EU far-right parties, and Brexit, this pacifying institution is facing unprecedented threats. Now Trump is signaling that he won’t wield the US’s peerless influence to try to ward off said threats. That’s strike two against the world order.

Strike three is Trump’s plan to attack the German auto industry. In the interview, Trump proposes to slap a 35 percent tax on BMW imports to the United States as a form of retaliation for building a plant in Mexico.

“I would tell BMW if they think they’re gonna build a plant in Mexico and sell cars into the US without a 35 per cent tax, it’s not gonna happen,” he says. “What I’m saying is they have to build their plant in the US.”

Here you see Trump replaying a domestic policy move of his — bullying specific companies into putting more manufacturing plants in the United States by threatening economic problems if they don’t comply.

But BMW isn’t an American company; it’s a German one. If the United States slaps this kind of tariff on a German company, Germany will likely retaliate against the United States. This is the early stages of what economists call a “trade war” — where countries make trading with each other harder to punish one side’s protectionism.

This, too, is an assault on the postwar order. Trade, like the EU, has both an economic and a political function. Its political function is to bind Western countries together, to align their interests and prevent trade wars that would slow down growth globally. By attacking a key company in one of America’s most important allies, Trump risks not only damaging the US economy but also alienating a critical partner in managing the global economy and keeping trade open.

Military, political, economic — this interview is a blueprint for war on the international order.

“Putin’s wish list”

There is only country that benefits from all of these moves: Vladimir Putin’s Russia.

Putin’s fundamental foreign policy goal is to restore Russia’s place as one of the world’s most powerful and influential nations. To do so, he wants to restore global politics to the way it was in the 19th century — when European countries saw each other as rivals rather than partners. This kind of “balance of power” world order would allow Russia to divide European powers by forming selective partnerships with some against the others — thus restoring Russian greatness.

Putin’s Russia is too weak, in political and military terms, to accomplish this on its own. The logical endpoint of Trump’s stated policies, regardless of whether that’s what he intends, is a fractured Europe that would be far less capable of standing up to Putin.

“Every [foreign policy] position Trump takes, starting from total ignorance around [a] year ago, is on Putin's wish list,” Garry Kasparov, the Russian chess master and dissident, tweets. “Brexit, Ukraine, NATO, EU, Merkel.”

Trump’s stated policy ideas, if implemented, would have the effect of accomplishing much of what Putin has dreamed of but that the Russian leader may have never have thought possible.

Now, with Trump taking office in a few days, it all seems very frighteningly real. Trump is proposing isolating America from its allies, and isolating these allies from each other. The only power that benefits is Russia, perhaps America’s most significant strategic rival. There is a country that Trump may soon make great again. The problem is that it’s not the US.

Watch: How Putin won Republicans' approval