With his diatribes against witnesses who cooperate with the government — “flippers” and “rats” — President Trump has become notorious for speaking like a mob boss. He is acting like one, too, turning U.S. foreign policy into a protection racket and soldiers into a strong-arm squad that needs to be paid off — or else.

Bloomberg News reports that, at the president’s insistence, the administration is formulating plans to demand a vast increase in the subsidies that allies pay to support U.S. forces on their soil. Trump wants countries such as Germany, Japan, and South Korea to pay the entire cost of those deployments — plus 50 percent! This “Cost Plus 50” formula would require those nations to pay five or six times as much as they currently do — and they currently pay a lot. Germany, for example, contributes $1 billion a year, representing 28 percent of the cost of 35,000 U.S. personnel based there.

Trump just got Seoul to increase its cost-sharing from $830 million to $924 million, representing more than 40 percent of the cost of keeping 28,000 U.S. troops in South Korea. But that’s only a one-year deal, so expect another bruising renegotiation with South Korea — and other allies. Trump has already been browbeating NATO countries to spend more on defense, apparently under the mistaken impression that the money will be paid to the U.S. Treasury rather than to their own defense ministries.

There is nothing novel or wrong about asking allies to pay more; past administrations have done so for decades. But unlike his predecessors, Trump shows no awareness of the benefits that the United States derives from its deployments. He is acting like a landlord demanding a rent increase from deadbeat tenants.

But our allies aren’t tenants — and they aren’t freeloaders. They are partners in a collective security enterprise that benefits the United States more than anyone else. With only 4.27 percent of global population, the United States has 24.4 percent of global GDP. Our defense budget is a relatively inexpensive investment in keeping this international system in business. Even at more than $700 billion, the U.S. defense budget consumes just 3.1 percent of gross domestic product.

And only a tiny portion of the overall defense budget pays for foreign deployments. Out of 1.3 million active-duty military personnel in 2016, just 193,422, or 15 percent, were deployed in other countries. It’s actually cheaper to keep U.S. troops abroad than to bring them home: North Carolina and Texas won’t contribute to their upkeep as Germany and Japan do. Also more useful: Troops overseas are a lot closer to the scenes of potential trouble than troops at home.

The countries with the largest number of U.S. troops — Japan, Germany and South Korea — have more than a million active-duty military personnel of their own altogether. America’s modest contribution, equal to 10 percent of their own armed forces, is primarily intended to deter a war with nuclear-armed foes such as Russia, North Korea or China that would be catastrophic for all concerned — including us. If U.S. forces weren’t there, our allies likely would go nuclear, and we could see dangerous and destabilizing nuclear arms races similar to the Dreadnought race before World War I.

America’s forward-deployed troops safeguard the three most economically important regions outside of North America — Europe, Northeast Asia and the Middle East. Our commitment has made possible the greatest expansion of freedom and prosperity — and the longest period without a great power conflict — in history.

Historians Hal Brands and Charles Edel note in their new book “The Lessons of Tragedy: Statecraft and World Order” that in the 1,000-year period between 900 and 1900, England was involved in some type of war in 56 out of every 100 years, and Russia experienced only a single quarter century of peace. Just between 1648 and 1789, the European powers fought 48 wars, “with some of them — the War of the Spanish Succession from 1701-1714 and the Seven Years’ War from 1756-1763 — being world wars in all but name.”

Seen from this historical perspective, the post-1945 period in which there has not been a single war between the great powers is a miraculous anomaly. This is not all due to the deployment of U.S. air, naval and ground forces — but a lot of it is.

If you want to see what happens when there is no country to keep the peace, I recommend Peter Jackson’s haunting World War I documentary, “They Shall Not Grow Old.” Many Europeans in the pre-1914 era were convinced that great power conflict was an impossibility; Norman Angell wrote a book in 1910 called “The Great Illusion” on this theme. Turns out that it was Angell and other peace activists who were operating under an illusion. Anyone who imagines that another great war is impossible today is just as deluded.

Brands and Edel fret that “after nearly 75 years of great-power peace and almost thirty years of post-Cold War primacy, Americans are losing their sense of tragedy. The U.S.-led international order has been so successful for so long, that Americans have come to take it for granted.” They’re right — and the proof is in Trump’s determination to mess with success.

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