I know we were working on them first and then had them in the 1940’s and the 1950’s, the Snark, Navaho and the Hound Dog missiles come to mind. We also had slower ones like the Matador and the Mace. IIRC, in the late 1950’s, they were considered dead end, President Eisenhower declared hypersonic missiles obsolete when we developed the Atlas and Titan 1A ICBM’s along with the Polaris SLBM’s and various IRBM’s. I don’t know if this is a red herring to sucker us to pay more money into something to weaken us or not. Well, even so, it would be nice to have a little insurance, we need to set up Hawk and Patriot missile batteries and bring back the Nike Sites and the BOMARC.
What we had back then was not in the same universe. Take the hound dog. 56,000 foot ceiling, Mach 2.1, 750 mile range. It basically had the capability of a cruise missile or jet fighter.
These things get up in low earth orbit, scream along 10 times that fast or more, and make their final plunge at 4000-5000 mph. They have basically worldwide range.