In a topsy-turvy world, yesterday’s enemy can be today’s friend. The U.S. has played this game (Germany, Japan, Italy, Vietnam and so forth). For another remarkable reversal of enmity and alliance, let’s drop in on the Kremlin.

In 1989, the Soviet Union limped out of Afghanistan, defeated by ragtag mujahedeen fighters determined to turn back Moscow’s bid to commandeer their homeland. Those mujahedeen forces evolved into the Afghan Taliban, ousted from power by America’s post-9/11 invasion of Afghanistan and now a dogged insurgent group bent on unseating the country’s democratically elected, U.S.-backed government.

After more than 15 years of fighting U.S., NATO and Afghan forces, the Afghan Taliban have not gone away. Instead, they remain a daunting threat to Afghan President Ashraf Ghani’s troubled administration, and to the 8,400 U.S. forces still in the country training Afghan security forces and hunting down militant commanders.

It’s a deadly, costly conflict with no end in sight. Predictably, Russian President Vladimir Putin’s making a bad situation worse.

The commander of U.S. forces in Afghanistan, Army Gen. John Nicholson, all but confirmed last week that Russia is supplying to the Afghan Taliban machine guns and antiaircraft weapons — armaments that the militant group is using to keep a tight grip on southern Afghanistan, and to kill Afghan and American troops. Asked if Russia was arming the Taliban, Nicholson said, “I’m not refuting that.” A senior U.S. military official told reporters in Kabul that Russia has ramped up its supply of arms to the Taliban in the past 18 months.

The Kremlin denies this, of course. But an earnest Kremlin denial has the credibility of a breathless Breitbart News post.

The Trump administration ought to tackle this problem — fast. Russia’s arming of the Taliban won’t turn the tide of the war, but it will perpetuate combat and make it that much more lethal. It’s hard enough to wear down an enemy as combat-hardened and resilient as the Afghan Taliban is. Another government helping the enemy is unconscionable, particularly because the Taliban’s targets include American troops.

The foreign policy think tank Stratfor suggests one motive for the Kremlin’s actions might be its desire to become an influential counterpoint to the U.S. presence in South and Central Asia, much the same way Russia’s intervention in Syria disrupts America’s Middle East policy. If that’s the case, the Kremlin’s thinking is short-sighted. As long as Afghanistan is at war, it destabilizes Central Asia — a region at Russia’s doorstep — and keeps intact a potential breeding ground for Islamic militants, including the Islamic State. To that group, Russia is as much an enemy as is the U.S.

The Trump team’s message to Moscow should be firm and blunt: Cease and desist. Russia is violating international law by arming the Taliban. It’s already coping with sanctions imposed because of its invasion of Ukraine — is it willing to weather more punishment? If Russia really wants to get involved, it should work toward what is the only bridge to peace in Afghanistan: negotiations that culminate in the laying down of arms and the integration of the Taliban into Afghan politics and society.

— Chicago Tribune