The ceasefire in eastern Ukraine is under strain as Kiev presses the West for more financial and military aid. Americans’ sympathies should go to both Ukrainians and Russians suffering in Vladimir Putin’s deadly geopolitical games, but Washington should stay out of the battle.

Putin obviously bears immediate responsibility for the conflict. However, Washington and Brussels consistently disregarded Russian security interests.

That still didn’t justify Putin’s actions and the results have been a horror for many Ukrainians, though Kiev’s military and nationalist militias have contributed to the unnecessary carnage. However, Moscow views the war less about expanding Russia’s “empire” than about protecting Russia from America’s expanding “empire.”

The U.S. should not intervene and treat Moscow as an adversary. To the contrary, Washington should stay out of the conflict and maintain a passable relationship with Russia.

After all, the latter, with a substantial nuclear arsenal, is the one power capable of annihilating America. Moscow also matters at the United Nations and in policy toward Afghanistan, Iran, North Korea, Syria, and terrorism.

Moscow’s behavior in Ukraine, though atrocious, poses no threat to America. Some emotional Ukrainian expatriates compare Putin to Hitler, but Russia isn’t a reincarnation of the Soviet Union, let alone Nazi Germany. Moscow is a declining, not rising power.

Ukraine obviously matters more to Europe than America. But Europe has a greater GDP and population than America (and much larger advantages over Russia). Yet almost all European states continue to disarm. No one is prepared to fight for Ukraine.

There also is a humanitarian call for action, but Ukraine ranks below many conflicts elsewhere. Some Ukrainians point out that Kiev gave up its nuclear weapons, leftovers from the Soviet arsenal, in return for international guarantees. But Washington never promised to act militarily.

Anyway, the allies have no cost‐​effective way to force Moscow to back down. Iraq, Russia, a major power with nuclear weapons and a deep sense of grievances, is certain to prove intractable and respond with great force.

Of course, the U.S. and European militaries are more powerful than Russia’s armed forces. However, the latter possesses the great equalizer of nuclear weapons. Moreover, with far more at stake, the Kremlin will bear greater costs and take greater risks.

Kiev wants additional military aid. But Moscow likely would respond in kind, just as it intervened more directly last year when Ukrainian forces began winning on the field. The stakes for Moscow are too high to yield.

Arming Kiev would put U.S. credibility at issue. If greater American efforts only led to higher Ukrainian losses, pressure would build for additional weapons and training, and perhaps much more, including airstrikes and ground personnel.

Ian Brzezinski of the Atlantic Council recently urged Congress to authorize NATO’s Supreme Allied commander “to deploy in real time against provocative Russian military operations,” that is, offer combat and start a war. Yet no policymaker of note in the West is prepared for war over Ukrainian separatism.

Finally, ramping up sanctions on banking and energy wouldn’t likely change Moscow’s behavior. There’s little European support for such a course. Putin could respond by expanding economic controls, political repression, and foreign adventurism.

Nor is a domestic crisis likely to yield a liberal, pro‐​Western government. Putin actually appears to be a pragmatic nationalist compared to more radical forces.

The best outcome would be a negotiated settlement recognizing Ukraine as nominally whole while according the Donbas extensive autonomy and guaranteeing no NATO membership or other Western‐​oriented military relationship for Ukraine.

Ukrainians insist that these decisions should be up to them. Kiev should set its own policy, but then bear the cost of doing so. Washington and Brussels should not support permanent confrontation and potential war with Moscow.

As I argue on Forbes online: “Hopefully the tattered ceasefire in the Donbas will hold and both sides will accept a compromise solution. In any case, the U.S. should keep its arms and troops home. Ukraine is not America’s fight.”