Existing, ramjet-powered "Sunburn" ship-killer missiles from Russia can skim the waves for 100 miles or so at Mach 2-plus; but this still offers the US Navy enough space and time to intercept them - or their launching ship or plane, anyway.
If China can get scramjets working, though, things might change. The ability to burn fuel in an airstream that is moving supersonically could offer a big jump to hypersonic speed at decent range. If China could build a shipkiller that flew at Mach 6-plus for a few hundred miles, it would be a bold American admiral who dared take his fleet anywhere near the Taiwan Strait: and that might enable Beijing to lean more heavily on the Taiwanese.
So, funnily enough, Chinese engineers visiting Cincinnati revealed that a lot of work on scramjets has been underway, and that models are about to begin testing up to Mach 5.6 in a new Beijing wind tunnel. Full details of the revelations are available from Aviation Week here.
Not that the Chinese appear likely to solve the problems real soon.
But the intent of the project is the important thing to keep in mind. If this doesn't work, perhaps other programs we don't know about will bear fruit.
The objective of even unlikely projects is key. The Chinese want to keep our carriers away from Taiwan. The article says Pekings wants to do this so they can "pressure" Taiwan, but that is silly. China could pressure Taiwan all day with our carriers sailing close by: Rain down missiles near Taiwan's ports, exercise off of Taiwan's coasts, cross into Taiwanese territorial waters or air space, whatever. We wouldn't launch air strikes and start a war over "pressure."
But what such a capability would provide is to keep our carriers away from Taiwan long enough to invade and conquer Taiwan.
Of course, we are working on solutions to the problem, too. We might not need to get our carriers close to Taiwan in order to fatally complicate China's invasion plans.
The deadly dance continues.