Hubris, Overreach, and Greed. It sounds like a law firm, but it is the theme of Alistair Horne's book Hubris: The Tragedy of War in the Twentieth Century (2015). In his book, Horne introduces us to the Greek concept of hubris, which is the fallout from a seemingly easy military victory followed by a dramatic downturn. Horne examines several military campaigns (some relatively obscure) and their far reaching effects.
Tsushima - 1905. The Japanese navy whips the powerful Russian navy. The campaign began with Japanese sneak attack on the Manchurian seaport at Port Arthur. (A precursor of actions to come.)
Nomonhan - 1939. Led by General Georgy Zhukov, the Russians stop the Japanese aggression in Mongolia with a sound defeat of Japanese ground troops. Japan turns its expansionist interests elsewhere (Hawaii and Pearl Harbor).
Moscow - 1941. Zhukov returns to the Soviet capital, followed shortly thereafter by reinforcements from Siberia, who no longer are concerned about Japan's aggression in Mongolia. Beginning in June, 1941 the Germans had advanced hundreds of miles to the suburbs of Moscow only to be turned back in November, 1941 by subzero temperatures and a series of savage counterattacks. You cannot begin to fathom the bloodshed. In six months over 7 million Soviet and German troops fought against each other. It is estimated that the Soviet army lost 950,000 men. 
We usually think of Stalingrad as the turning point of the war on the Russian front, but Horne writes convincingly that Moscow was the real key and if the capital had fallen the Soviet Union probably would have collapsed. Another take away is that the Russian people have a capacity to withstand tremendous suffering (even from their own leaders) and then dish it out to invaders.
Midway - 1942. Japanese expansion in the Pacific is checked by the U.S. fleet. In a shift from conventional naval warfare, these two powerful naval forces never were within firing range of each other. Planes launched from aircraft carriers inflicted the main damage. The Japanese armada got the worse of it. American torpedo bombers sunk three Japanese aircraft carriers - the pride of their fleet.
Korea and Dien Bien Phu - 1950-54. U.S. General Douglas MacArthur overextends American involvement by striking into Chinese territory, which left his troops vulnerable to vicious North Korean and Chinese counterattacks. The war stalls into a bloody stalemate. Later in 1954, the French garrison near the Laotian border at Dien Bien Phu falls to an underdeveloped but impassioned military, which set the stage for America's disastrous intervention in Vietnam. (Some of us remember the comparison between Dien Bien Phu and the siege of Khe Sanh in 1968.)
Another aspect that all these campaigns have in common is that often countries attack other countries because they believe that their adversaries are "inferior." The Russian thought the Japanese where inferior at the time of Tsushima (and Japan was anxious to prove that it was not). The Japanese attacked the Chinese in Manchuria for the same reasons. The Americans and British grossly underestimated the piloting skills and the aircraft of the Japanese air force. The Germans attacked the "subhuman" Russians and when they captured Russian soldiers they didn't even afford them prisoner-of-war rights in accordance with the Geneva Convention. Demonizing or believing in one's superiority over another people, race or culture always leads to prolonged bloodshed.
Personal postscripts: This last year I've become quite the Horne fan. (See an earlier postings on his 1960 book about Verdun, The Price of Glory.) In his acknowledgements, Horne gives kudos to Sir John Keegan and his early mentor, Sir Basil Liddell Hart, who wrote a recent discovery of mine Sherman: Soldier, Realist, American. Horne talks about how Hart and others taught him the basics of "judicious" analysis of history. Lessons on display in Hubris.
