Since Donald Trump assumed power as the U.S. President in early 2017, the world has witnessed an unprecedented level of uncertainty about U.S. East Asia policy and other regions alike. Yet, now there is enough supporting evidence to interpret Trump’s East Asia policy highlighted by a shift from his enthusiasm to pursue bilateralism-based “America First” posture to both bilateral and multilateral approaches through economics-security nexus. In any case, Korea peninsular nuclear crisis, and the China factor to a lesser extent, serves as the determinant to this noticeable shift. Also, after the first 90 days in power, Trump may have learned more about the correlation between regional economic and security cooperation in the pressing quest for engagement, thus also marking a shift from removal to embrace of the legacy of predecessor Obama’s regional policy.