There were various treaties made with the Soviet Union that limited such defences (1-2 sites per country?) as they were seen as destabilizing by weakening MAD. Reagan’s Star Wars program was both an attempt to develop such capabilities and spend out the Soviets. People thought it worked, I guess.
I think some of the theatre missile defence systems have a ballistic capability and they might do well against individual launches. Not sure there’s much that can be done vs SLBM other than hope.
