I was living in the States during the last half of that war. It's a very hard subject for most Americans to address, even to this day. In spite of all their efforts, the billions of dollars spent, and their high casualty count (~200K), in the end, the war was lost to the Communists.
Many blame the American leaders of the time for how they conducted the war (a program of 'limited' war), but it did accomplish it's purpose of keeping China out of the war, and prevented a possible WWIII.
It was the worst mess the Americans have ever gotten themselves into. The theory is; they learned a lot from that mess, but after 16 years they're still in Afghanistan, and with no end yet in sight.
Selkirk