US Pacific Command commander Admiral Timothy Keating was in Korea recently praising the alliance:

Commander of the U.S. Pacific Command says South Korea is a highly important U.S. ally and vowed to continue close bilateral cooperation.

Admiral Timothy Keating visited Korea during his tour of U.S. bases in Asia. He met with Defense Minister Lee Sang-hee Friday and said that it is meaningful to visit South Korea at a time of escalating North Korean tension. He said his visit will send a message of firm Washington-Seoul alliance to Pyongyang.

He said key officials of the new U.S. administration know well that East Asia is an important region.  [KBS Global]