U.S. presidents have been keeping this situation in check for 60 years through diplomacy

Er, not exactly.........in 2003 North Korea withdrew from the NPT, which it had acceded to in 1985, when they were discovered to be illegally enriching uranium. Since then they have developed nuclear weapons and ballistic missiles in defiance of UN Security Council resolutions 1718, 1874, 2087, 2094, 2270, 2321 and 2371 which brings us to the present situation.