Excellent Wiki summary of what promises to be a whole new arms race.
Now that arms treaties are starting to control the ICBM threat, a whole new doomsday concept is arising to take its place: a weapons platform that can be mistaken for a nuke even if it isn't one.
I see the Russians are already hip to the hypersonic threat, and busily working on a counter to it. But we are ahead! Its a replay of the whole MIRV thing.
Only the defense industries on both sides can really look forward to this. Jobs, careers, power, funding...Dr Strangelove all over again...my precious bodily fluids...my Life Essence...