Depends on what you consider to be a "military response", but USA has already mobilised a military presence in South Korea, sent a battleship fleet and today it's is reported that the response to North Korea's ICBM test is ... "
US and South Korean forces, in response, engineered what was meant as a show of force for Pyongyang, with soldiers from the allied nations firing "deep strike" precision missiles into South Korean territorial waters. The missile firings on Tuesday (Wednesday, NZ time) demonstrated US-South Korean solidarity, the US Eighth Army said in a statement."
https://www.stuff.co.nz/world/asia/9...to-the-yankees