Germany is refusing to meet its commitments to NATO and the U.S. by failing to invest in its own defense. This sets up some interesting decisions for Trump.

The world’s fourth-largest economy spent $37 billion — 1.2% of its economic output — on defense last year, according to government figures. That is far short of the 2% set by NATO and a third of the 3.6% of gross domestic product that the United States spent in 2016, according to NATO figures.

That shortfall by Germany and other NATO countries is why Trump renewed his call in a speech to Congress on Feb. 28 for NATO members to pay their fair share of defense costs. “Our partners must meet their financial obligations,” Trump said. “Now, based on our very strong and frank discussions, they are beginning to do just that. In fact, I can tell you that the money is pouring in.”

That’s not quite the case in the German capital. The federal government plans to increase its military spending by $2.1 billion this year. It would bring total spending to $39 billion, a 5.4% annual boost. The increase pales in comparison with the 10%, or $54 billion, hike in U.S. defense spending Trump proposes for 2018.

Chancellor Angela Merkel, who will meet with Trump at the White House on Tuesday, recently announced plans to add 20,000 soldiers to the Bundeswehr to bring the force to nearly 200,000 but not before 2024, and the increase merely offsets recent cuts in troop strength.

Here’s the thing… the United States has invested billions of dollars for the past 80 years to provide a military defense for Europe and Europe has benefited from that by being able to spend their money on rebuilding their economies and infrastructures after WWII. But while there were some altruistic motivations for that, the real reason was that it was in the best interests of the U.S. to do so. The macropolitical reasons were that if Russia were to ever bulge out of its borders in a quest for world domination, it will most likely have to go through Europe before getting to America. American leaders invested in European defense because we would rather fight the Russians on the continent of Europe and let them exhaust their energy on that soil than let them do so on the shores of New Jersey.

While the Russian threat has ebbed in recent decades, we are right of the precipice of a new Angry Bear with the face of Putin. He has already invaded Ukraine, created a virtual satellite state in Syria, and is threatening Poland and other former Eastern Bloc countries. One would think that European nations would see the threat and act accordingly, but the memories of WWII and the abject pacifism remains a powerful cultural phenomenon.

So what should the U.S. do? If we withdraw from Europe and leave them to themselves, the threat of war increases. And in the event that another European war breaks out, it is inevitable that the U.S. will become involved. Or, in another scenario, Germany’s inability to defend themselves with conventional forces may lead them to launch a nuclear defense in the face of a Russian assault, thus starting the nuclear war that we have spent 80 years trying to prevent. But if we continue to defend Europe with American forces, we are expending a lot of money to prevent an eventuality that may never come.  How much American money should we spend to defend countries who refuse to adequately defend themselves?

What will the Trump Doctrine be?