Another work from about the same period that should not pass unmentioned is Christopher Anvil's novella "Pandora's Planet," later expanded into a novel of the same name. Anvil, most often published in Astounding and Analog, took a contrarian, sardonic, and often very funny look at things, and "Pandora's Planet" shows him at the top of his form, with bumbling invading aliens trying to deal with humans who are both smarter than they are and, except for lacking starships, more technologically advanced, too.
During the 1960s and 1970s, no doubt under the influence of the Vietnam War, interest in military science fiction waned. The military generally came under a cloud during those turbulent decades. One interesting exception to the rule here is the rise in those same decades of fantasy series chronicling enormous wars, most often against the power of evil. The archetype, of course, is J. R. R. Tolkien's The Lord of the Rings. I think such works became popular for a couple of reasons: first, who was good and who was not was very explicitly defined-which was not always the case in either the real world or the more realistic forms of science fiction-and, second, the stories were set in worlds so far removed from our own as to distance the readers from the everyday mundanities of life.
Fred Saberhagen's Berserker series of science-fiction adventure tales solved the problem of good guys and bad guys by making the enemy a fleet of robot starships programmed to root out life wherever it might be encountered (a theme also used earlier, not long after the end of World War II, by Theodore Sturgeon in "There Is No Defense"). In The Men in the Jungle, Norman Spinrad solved it by not solving it; as far as anyone can tell, there are no heroes in the story, only villains of one stripe or another-again, a motif disturbingly close to real life.