The older advisers of North Korea’s Supreme Leader Kim Jong Un may be keeping quiet about a dark part of their country’s past combat history — shared below — if reports are true he has now deployed troops to assist the Russian war effort in Ukraine.

On June 19, 2024, during a visit by Russian President Vladimir Putin to Pyongyang, the two leaders signed a mutual defense pact committing their countries to provide military assistance to each other without delay should either be invaded. It upgrades their relationship to a “comprehensive strategic partnership.”

Less than two months later, on Aug. 6, in a surprise attack, a large Ukrainian force entered western Russia, occupying villages in the Kursk region. Ironically, Putin, who had initiated the conflict in February 2022 by invading Ukraine, called the attack a “large-scale provocation.” Apparently the Russian dictator believes invasions are only allowed to go one way.

However, it may well have been this Ukrainian invasion that triggered North Korea’s obligation under its defense treaty with Russia to send troops to assist Moscow. While Ukraine reports that North Korean soldiers are now fighting alongside Russians, the Kremlin denies it.

Meanwhile, South Korean news reports say that at least six North Koreans have already died as a result of a Ukrainian missile attack on Russian-occupied territory near Donetsk during the first week of October. What should concern Kim at this point as well, if it has even been reported to him by his commanders, is the fact that as soon as the North Koreans were on Russian territory, at least 18 deserted their units.

South Korean satellite photographs support the claim of a North Korean presence. They reveal at least 1,500 North Korean special forces in Najin Port, boarding Russian transport ships in mid-August, who are then taken to Vladivostok, Russia. Photos also show more North Korean troops on a parade ground in Khabarovsk in southeast Russia.

While experts question just how effective the North Koreans will be due to their outdated equipment and limited battlefield expertise, history supports their skepticism.

If Kim sent troops to Russia to provide them with combat experience as some experts believe, one wonders if the North Korean despot — who at age 40 was born well after the Vietnam War — was informed about an embarrassingly dark, disastrous, and short-lived experience suffered by a squadron of North Korean jet fighter pilots sent to assist Hanoi by Kim’s grandfather in that conflict. For long it was probably one of the best kept secrets of the Vietnam War that, for a brief period in 1967 and without knowing it, American fighter pilots were engaging North Korean fighter pilots.

The experience was disastrous for the North Koreans as every pilot who went airborne to engage a U.S. aircraft was shot down. At least 14 North Korean pilots died, seemingly unable to adapt to that day’s aerial fighting tactics, instead relying on those used during the Korean War years earlier. And, since they were flying North Vietnamese aircraft, Hanoi was losing planes at an incredible rate. It resulted in Hanoi politely telling Pyongyang “thanks but no thanks” as it sent the remaining pilots back home after only serving in Vietnam for a few months.

Today, in Vietnam’s Bac Giang province, there is a cemetery containing the graves of those North Korean pilots whose bodies were recovered.

One of the greatest warriors and diplomats of the 20th century — Winston Churchill — gave a speech in 1948 in which he said, “Those that fail to learn from history are doomed to repeat it.” North Korea’s Kim has failed to learn from his country’s Vietnam War experience the result of taking on a better trained foreign force. It is his warriors who will suffer the consequences of his ignorance.

James Zumwalt is a retired Marine infantry officer (lieutenant colonel) who served in the Vietnam War, Panama and Operation Desert Storm. He is the author of three books and hundreds of opinion pieces in online and print publications.