A Ukrainian soldier, left, and two U.S. soldiers climb on an armored military vehicle as they attend joint military exercises at the Yavoriv training ground, near the western Ukrainian city of Lviv, on July 4. (Ivan Bobersyy/European Pressphoto Agency)

Robert H. Scales is a retired Army major general, a former commandant of the U.S. Army War College and the author of the forthcoming book “Scales on War.”

In November, while visiting the headquarters of the U.S. Army in Europe, I received a briefing on the performance of the Russian army in Ukraine. In a perfunctory tone, the young intelligence briefer recited the details of the July 2014 Battle of Zelenopillya, in which a single Russian artillery “fire strike” almost destroyed two Ukrainian mechanized battalions in a few minutes.

I couldn’t help imagining a U.S. armored battalion subjected to a similar fire strike. I realized then that Ukraine had become Russia’s means for showcasing what might happen if we ever fought a firepower-intensive battle against it. “You know, guys,” I mused in the moment, “this is the first time since the beginning of the Cold War that an American war-fighting function has been bested by a foreign military.”

This revelation was all the more disturbing because artillery firepower has been a centerpiece of U.S. land warfare for almost a century. At Normandy, the Germans had nothing good to say about the quality of U.S. armor and infantry. But they feared U.S. artillery. The Germans could not mass fire across unit boundaries. But an American invention, the coordinated-fire “time on target,” could bring hundreds of guns to bear on a single target, delivering thousands of rounds simultaneously. The effect on the Germans was devastating.

During the Gulf War, the Iraqis most feared what they called “steel rain.” The “rain” consisted of hundreds of thousands of flashlight-size bomblets stuffed into artillery shells and rocket warheads. U.S. counter-fire radar, mated to multiple-launch rocket systems (MLRS), smothered Saddam Hussein’s much-vaunted artillery in a massive series of day-long barrages. The Iraqi artillery never again posed a threat to our troops.

The Ukrainian experience serves as a deadly analogue for what might happen to U.S. artillery should we fight the Russians or a Russian surrogate. New Russian firepower systems now outrange ours by a third or more. They have improved on our steel-rain technology by developing a new generation of bomblet munitions that are filled with thermobaric explosives. These munitions generate an intense blast wave of exploding gases that are far more lethal than conventional explosives. A single volley of Russian thermobaric steel rain delivered by a single heavy-rocket-launcher battalion will annihilate anything within an area of about 350 acres.

Tragically, all of America’s steel-rain munitions — millions of shells and warheads — are gone, intentionally destroyed by the past two administrations in a sacrifice to the gods of political correctness. They agreed to give up all submunition weapons after other nations (which had no steel rain) signed a treaty banning such weapons because they produce too many duds that remain on the battlefield and pose risks to civilians. Russia, China and Israel believed they had real wars to fight and ignored the treaty. As a result, a Russian heavy-rocket-launcher battalion firing steel rain produces a lethal area at least five times greater than a U.S. MLRS battalion firing conventional high-explosive warheads.

The performance of Russian artillery in Ukraine strongly demonstrates that, over the past two decades, the Russians have gotten a technological jump on us. The United States’ strategic drones, the ones that plink terrorists from bases in Nevada, are more advanced than Russia’s. But Russian tactical drones, which spot for artillery, are far superior (and far more numerous) than ours. In 2014, when the Battle of Debaltseve began, the Ukrainians reported that as many as eight Russian tactical drones orbited over their heads at any one time.

Additionally, the electronic warfare technology demonstrated by the Russians in Ukraine is the best in the world, far better than ours. During the 240-day siege of the Donetsk airport, the Russians were able to jam GPS, radios and radar signals. Their electronic intercept capabilities were so good that the Ukrainians’ communications were crippled. Ukrainian commanders complained that a punishing barrage would follow any radio transmission within seconds.

Does this mean that the Russian army is superior to ours? No, not at all. If we fought the Russians today, we would win. Ours is a highly trained force of half a million soldiers. Two-thirds of Vladi­mir Putin’s 800,000 soldiers are one-year conscripts whose fighting skills are questionable. The Russian air force is also no match for ours. But the Ukrainian experience tells us that the cost in blood of any such contest would be high.

A tragic decline of a war-fighting arm that once was our Army’s most lethal should serve as a cautionary tale. This diminution of war-fighting capability in our European army comes at an inauspicious time: when Republican presidential nominee Donald Trump publicly questions the value of defending Europe and the Obama administration is spending hundreds of billions of dollars on big, high-tech systems optimized to fight at sea in Asia. Yet in today’s wars, more prosaic weapons such as small arms, mines and artillery are killing our soldiers. Add in the fact that we have forfeited what formerly was an overwhelming U.S. battlefield capability, and we can only imagine what deadly consequences may result from our good intentions.