A space force
At the beginning of the nuclear era, the U.S. Army, Navy, and Air Force demanded their own nuclear role. As a result, not only did a lot of money got wasted, but nearly topped the world into an unprecedented catastrophe.
The Army’s nuclear ambitions burdened the U.S. with too many short-range nuclear weapons, which turned out to be some sort of open invitation to war planners to imagine a great battlefield role for Hiroshima-style warheads.
The Air Force kept its strategic bomber force for many years, right after it was rendered completely obsolete by intercontinental missiles. The balance between these land-based and sea-based missiles was equally driven just as much by Navy-Air Force rivalry, as by military rationality.