The U.S. National Defense Authorization Act for the year 2015 passed the House of Representatives last week.
It stipulates that the Secretary of Defense should assess and identify opportunities for boosting missile defense cooperation among South Korea, the U.S. and Japan.
If enacted, the Pentagon will evaluate whether the three countries can share more military information, have their missile systems integrated and conduct joint exercises.
After picking up the information on Tuesday experts in Seoul say Washington's move could face resistance as South Korea does not want to share military intelligence with Japan.
The passing of the bill comes in line with a Japanese media reporting that U.S. National Security Adviser Susan Rice discussed the matter with Japanese Prime Minister Shinzo Abe.
The Yomiuri Shimbun report said Rice suggested immediately sharing information among the three nations if South Korean radar detects a North Korean missile launch.
Attention now lies on how the South Korean government will react -- and if it will react -- to Washington's move especially considering a U.S. Congressional Research Service report last year said Seoul would benefit the least given its close proximity to Pyongyang.
Laah Hyun-kyung, Arirang News.