Russia has suffered heavy losses and slow progress in Ukraine has raised doubts about the strength of the military.

Video of Russian tanks and other vehicles being destroyed in Ukrainian attacks has made the losses hard to hide, as US officials estimate that several thousand Russian troops have been killed during the invasion. There is a sense of disarray due to reports that high-ranking Russian officers have been killed on the front lines.

Russia's poor performance and Ukraine's surprisingly strong resistance have drawn comparisons to the Winter War between the Soviet Union and Finland in 1939 and 1940.

The huge Red Army was inflicted with a lot of casualties during the 105-day war.

Michael Kofman is the research program director for the Russia Studies Program at the think tank.

Kofman told War on the Rocks on March 6 that the Winter War led to the belief that the Soviet military is bad.

German perception of Soviet military weakness proved to be incorrect.

The Winter War

Finnish troops on skis winter war
Finnish infantry on skis in October 1939. Ski-mounted Finnish troops inflicted heavy losses on the Soviets.
Hulton Archive/Getty Images

The Winter War was launched by the Soviets after Moscow failed to get the Finns to give up their border territory near Leningrad.

It should have been a no contest. Before the war, the entire military of the country numbered around 280,000 men, with only 400 pieces of weaponry.

The Leningrad Military District alone had 500,000 men, 5,700 field guns, 6,500 tanks, and 3,800 aircraft.

Stalin was so confident that he rejected a cautious plan presented by the Red Army Chief of Staff that called for massive, concentrated thrust through the main line of defense.

Soviet artillery Finland winter war
A motorized detachment of Soviet heavy artillery advancing into Finnish territory in late December 1939.
ullstein bild/ullstein bild via Getty Images

Stalin chose a plan similar to Germany's plan to invade Poland.

Soviet planners thought the operation would last about two weeks. The Finns held their own during the first six weeks of the war.

The Mannerheim Line in the Karelian Isthmus, a stretch of land west of Leningrad, was not penetrated by the Red Army.

Long Red Army columns confined to the few existing roads and its advances through dense forests exposed it in a way that negated its numerical advantage.

The Finns used ski troops and winter camouflage in the cold weather. Soviet commanders did not initially equip their troops with the same gear.

Soviet soldiers Finland winter war
Dead Red Army soldiers on a road after the Battle of Suomussalmi, December 31, 1939.
Hulton-Deutsch Collection/CORBIS/Corbis via Getty Images

The Finns would cut off and surround Red Army columns, a tactic they called "motti", and then destroy the Soviets piecemeal.

About 630 Finns were killed at the Battle of Tolvaj. The soviet division was effectively destroyed at the battles of Suomussalmi and Raate Road.

Stalin made changes by February. The Red Army was reorganized and the Soviet plan was restructured to focus on a concentrated drive through the Mannerheim Line.

In February 1940, a huge offensive broke through. The Finns faced complete defeat and had no choice but to agree to negotiations.

'A paper tiger'

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A Finnish radio announcer describes the shoot-down of a Soviet bomber by a Finnish fighters in 1939.
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In the Moscow Peace Treaty signed on March 12, 1940, the Soviets cut off the Barents Sea from the rest of the country.

It cost the Soviets a lot. In 105 days, as many as 140,000 Red Army soldiers were killed and more than 3,500 tanks and aircraft were destroyed. Finns were killed at a higher rate than Finns lost tanks and aircraft.

The Winter War had consequences outside of Finland.

Hitler believed that the Red Army was incapable of fighting the Wehr because of its poor performance and the effects of Stalin's military purges.

Hitler told his generals that he had only to kick in the door and the structure would fall.

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Slain Red Army troops and Soviet tanks that were salvaged for use by Finnish forces, March 1940.
Bettmann via Getty Images

Hitler had lost his confidence. The Red Army fought all the way into Berlin after the Nazis inflicted over a million casualties on the Soviets.

Both the Germans and the Finns saw first-hand the power of the Red Army after Western aid and the lessons of the Winter War.

Kofman warned that judging the Russian military's capabilities based on its performance in Ukraine may be misguided.

I'm worried we're going to walk away with a decent assessment of all the problems in the Russian military but also with a wrongheaded notion that the Russian military would fight in a regional context.