"High Treason" is a 1966 science fiction short story by Poul Anderson.
The story consists of the last words of Colonel Edward Breckinridge of Earth's space-bound armed forces, as he is about to be executed by being ejected without a space suit into the vacuum of interstellar space. He has been allowed to record his words (and thoughts and images) into a "memory cube", so as to preserve his version of events for posterity.
Humanity is about to lose its war with the alien Morwain. As a desperate last throw, Breckinridge had been ordered to launch an attack which would obliterate all life on a strategic Morwain planet - a planet which Breckinridge had visited before war had broken out and befriended some of its inhabitants, and which is important to Morwain culture and history.
Breckinridge protests to his superior, General Wang, pointing out that until then the war had been conducted "cleanly", mainly in space battles which did not harm civilians. Wang responds that he had lost much sleep over this issue, but that there is no other way to win the war. He offers to relieve Breckinridge, but Breckinridge says he will do it.
However, setting out with sealed orders and the true mission kept secret from his underlings, Breckinridge launches a hopeless attack against a superior Morwain force in a different sector with the explicit intention of having his force be destroyed so that Wang could not use it for the original mission. He hopes to be killed himself, but survives. When he returns with the battered remnants of his force, he is court-martialled on the charge of high treason and sentenced to death. Defeat is now inevitable.
Breckinridge states that his trial had been eminently fair and does not contest the sentence. Still, he considers his decision to have been morally justified, since even defeat and occupation of Earth are preferable to the atrocity of destroying an entire populated planet.
Moreover, Breckinridge feels that Earth's war with the Morwain, which developed and escalated from border disputes and incidents, had been mistaken to begin with - especially since humans and Morwain should have united to confront the danger of the monstrous, Nazi-like Bilturs expanding across space. An atrocity such as Breckinridge had been ordered to commit would have created such bitterness and hatred as to rule out such an alliance.
Throughout his monologue, Breckinridge speaks as a professional military man, despite his act of treason. As such, he expresses strong disdain for the anti-war "Brotherhood of Love" and does not want them to posthumously claim him. This clearly reflects the writer's dislike of the Hippie "Counterculture" and its opposition to the Vietnam War at the time of writing.
Commentator Conrad Hilton wrote:
Poul Anderson's 'High Treason' gives a very sympathetic depiction of a military officer whose act is - from the strict legal point of view - precisely what the story's title says. Still, there are moral considerations which override an officer's duty to obey orders, and there are prices for winning a war which are unacceptable. When faced with the choice of committing an act of genocide or letting Earth lose the war, the protagonist chooses - on his own authority and consulting no one - to let Earth lose the war. Anderson clearly seems to endorse his choice. (...) Reading this story should give a pause to those who hastened to categorize Anderson on the basis of his support for the Vietnam War.