LTV/Vought demonstrated the first HTK ASAT missile in 1985.....TWENTY YEARS AGO!!! Many of the guidance techniques are still used in PAC-3/THAAD etc.
It was decommissioned immediately after demonstration by Reagan, IMO, as a bargaining chip with the Russkies.
I find it hard to believe that we don't have a ready-to-go system if needed. Or cheap "sat-mines" that could be steered in orbit to 'accidentally' whack some other sat in orbit.