Eugene Volokh reminds us that there was another case similar to the bin Laden killing--and it happened a little over 68 years ago.
Following the attack on Pearl Harbor, Admiral Yamamoto was probably the most hated man in America, roughly on a par with you-know-who. There was little question what we would do if we found him.
Well, on April 14, 1943, naval intelligence decoded a Japanese message detailing Yamamoto's itinerary during his tour of military bases. Roosevelt's order to the Secretary of the Navy, Frank Knox, was simple: "Get Yamamoto."
Eighteen handpicked pilots from three fighter groups were chosen for the mission. On April 17, flying P-38 Lightning fighter planes, they ambushed and shot down Yamamoto's plane over the Solomon Islands.
That was, indeed, an assassination. Even the pilots involved admitted as much. And I, personally, have absolutely no qualms about it. It was the right thing to do.
Onward and upward,
airforce