I know that there is a nuclear triad consisting of intercontinental ballistic missiles, submarine-launched ballistic missiles, and bombers, but are the bombers even necessary? In a war involving America, the Soviets/Russians or Chinese, I can't think of any scenario in which bombers can do something ICBMs and SLBMs can't. The only real advantage I can think of is that they can be called back, but what are the chances that one of those three powers would launch a nuclear attack then cancel it?