The iron law of international relations was expressed 2,000 years ago by Thucydides in his “History of the Peloponnesian War”: “The strong do what they can and the weak suffer what they must.” Will Rogers voiced the same sentiment in describing the art of diplomacy as “saying ‘nice doggie’ until you can find a rock.” Everything else is choreography.

The Sermon on the Mount was a bravura performance for peace. But the message clearly hasn’t stuck. War — the legalization of first-degree murder — remains mankind’s worst, incorrigible scourge. President Donald Trump recognizes that he was elected president of the United States, not president of the world. He instinctively is inclined toward the wisdom of President George Washington’s Farewell Address, i.e., no entangling alliances, no permanent friends, no permanent enemies. He instinctively embraces the foreign policy articulated by Secretary of State John Quincy Adams in his landmark July 4, 1821, address to Congress: Eschew racing abroad in search of monsters to destroy, as we did in squandering trillions of dollars and countless lives in Vietnam, Afghanistan, Iraq and Libya, among other misadventures. He intuitively acknowledges the prescience of Sen. Henry Clay in opposing U.S. intervention to support the 1848 Hungarian Revolution:

“Far better is it for ourselves, for Hungary, and for the cause of liberty that, adhering to our wise, pacific system, and avoiding the distant wars of Europe, we should keep our lamp burning brightly on this western shore as a light to all nations, than to hazard its utter extinction amid the ruins of fallen or falling republics in Europe.”

Much ink has been spilled over the pyrotechnics that went off in the Feb. 28 Oval Office meeting between Ukrainian President Volodymyr Zelenskyy and Trump. It made for magnificent theater. But it clouded the question that has never been answered since Russia attacked Ukraine more than three years ago: How involved should the United States be in this conflict?

Russia is no existential threat to the United States. Vietnam discredited the domino theory, which holds that if Russia is not rebuffed in Ukraine, then NATO members will be next in the queue. Indeed, history teaches that if Russia occupies Ukraine, it will be more likely bogged down with chronic insurrections and staggering occupation costs that would lessen its threat to NATO. The struggles of the Soviet Union in Central and Eastern Europe during the Cold War in putting down recurring uprisings in East Germany, Poland, Hungary and Czechoslovakia are convincing.

The United States has spent nearly $200 billion on Ukraine since the Russian invasion. That money would have been better spent on the Constitution’s foreign policy of invincible self-defense or on paying off our staggering $36 trillion national debt. If Europe feels threatened by Russia’s invasion of Ukraine, Europe should foot the bill of Ukraine’s defense. Every country in the world acts in its self-interest. The United States should not be the sole country to bear the responsibility of world philanthropy.

It’s worth noting that Trump has gone astray at times in his concern for U.S. financial interests in Ukraine. His proposal that the United States continue to fund Ukraine’s war in exchange for rare earth metals would make us indistinguishable from mercenaries like the Hessians who fought for the British against the American Revolution. Detractors of Trump’s resistance to military support for Ukraine sermonize that Russia’s invasion violated international law. True enough. But international law is like a spider’s web. It snares the weak but is thrashed by the strong. Past U.S. military adventures such as our 2011 intervention in Libya also flouted international law.

The wisest and cost-free influence of the United States abroad is the influence of example. By practicing government by the consent of the governed, honoring unalienable rights to life, liberty and the pursuit of happiness, and celebrating the rule of law, we would inspire people in other countries to do likewise.

That would mark our finest foreign policy hour.

Armstrong Williams (www.armstrongwilliams.com; @arightside) is a political analyst, syndicated columnist and owner of the broadcasting company, Howard Stirk Holdings. He is also part owner of The Baltimore Sun.