Given the effectiveness of A2/AD, do NATO countries plan to role out comparable capabilities? An American equivalent to the missile DF-21D, based on islands such as Guam, Okinawa, Wake Island, Diego Garcia, etc (I wont list all of the possible locations - but there are a lot), could serve to deny China's navy access to it's near seas in a time of war, and also prevent them from operating freely in the Pacific, Indian, and even Atlantic Oceans, given the massive advantage that USA and it's allies have in strategically located islands in these regions. The missile would also benefit from superior US missile technology (remembering that the DF-21 appears to be a clone of 80s era American technology), superior American radar, superior American intelligence/satellite/sensor networks, and so forth.

Has the USA or any NATO allies invested a substantial R&amp;D effort into developing a ASBM system similar to China's?