I know Afghanistan is probably one of the wars Russia got bogged down in, and that's not wrong. The Soviet invasion of Afghanistan is commonly referred to as the USSR's Vietnam. It was a drain on men and materials and contributed to the end of the Soviet Union. Getting rolled by an insurgency effort by the Mujaheddin and Chernobyl melting down in the same decade presented a total catastrophe on the domestic and international front that the Soviet Union simply could not absorb, among many other things. When it comes to badly executed wars, we have to go back to 1940 and Stalin's Finland operation that was a total nightmare.
Did the Soviet Union prevail? Sure—but the butcher's bill was immense. History repeats itself. We're going to be hearing that a lot. The Imperial War Museum and Britannica have good summaries of the Winter War the USSR fought with Finland. There are some similarities with the current situation in Ukraine. Finland was wary of Soviet expansion. They wanted a defensive pact with Poland, Estonia, and Latvia. That effort collapsed in the 1920s. The country did sign a nonaggression pact with Moscow in 1932, but the Finnish government's fear of invasion was not assuaged. The Russian invasion of Poland only proved that something was coming, and it did in 1940 when Stalin wanted to redraw the border between the USSR and Finland to give the area around Leningrad (St. Petersburg) some breathing room.
The Imperial War Museum noted that despite one million men invading on three fronts—the Soviets got bogged down. Finnish troops had no outside help in this short war. They would use hit and run attacks via skis. They knew the land. They fought tooth and nail, even raiding dead Soviet soldiers for ammunition when supplies ran low (via IWM):
Finland declared itself neutral at the start of the Second World War, but the Soviet Union demanded concessions. Finland delayed, using the time to mobilise its army and seek help from Sweden and the Western Allies, including Britain and France, but with little success.
A faked border incident gave the Soviet Union the excuse to invade on 30 November 1939. The Red Army was ill-equipped, poorly led, and unable to deal with the Finnish terrain and winter weather. Though small and under-resourced, the Finnish Army was resilient, well-led and was able to use knowledge of the terrain to good effect.
[…]
By early February 1940, the Finnish Army was exhausted and their defensive lines eventually overrun. Outside help never materialised. Finland was forced to sign the Treaty of Moscow on 12 March 1940, which ceded 11 per cent of its territory to the Soviet Union.
Britannica has a more detailed analysis, though this war takes a dark turn when Finland reached out to Nazi Germany for help which led to the Continuation War:
Soviet troops totaling about one million men attacked Finland on several fronts. The heavily outnumbered Finns put up a skillful and effective defense that winter, and the Red Army made little progress. In February 1940, however, the Soviets used massive artillery bombardments to breach the Mannerheim Line (the Finns’ southern defensive barrier stretching across the Karelian Isthmus), after which they streamed northward across the isthmus to the Finnish city of Viipuri (Vyborg). Unable to secure help from Britain and France, the exhausted Finns made peace (the Treaty of Moscow) on Soviet terms on March 12, 1940, agreeing to the cession of western Karelia and to the construction of a Soviet naval base on the Hanko Peninsula.
The point here is that Russia's recent venture into Ukraine and getting bogged down post-invasion is nothing new. In the Winter War, which only lasted three months, the Soviets lost nearly 170,000 men. Totaling the dead, wounded, those afflicted with frostbite, and illness, the Soviets incurred nearly 400,000 casualties. This war would have even dire consequences for Russia, as Nazi Germany saw the effects of this war and the shoddy Soviet tactics and strategy, which gave Hitler confidence to plot the breaking of his non-aggression pact with the USSR to launch his invasion of the country.
Based on Ukrainian reports, Russia has lost some 4,500 men in less than a week. That's roughly how many troops we lost during the entire Iraq War, including our occupation of the country post-2003.
