WASHINGTON (AP) — A new agreement with South Korea on sharing the cost of keeping U.S. troops on the Korean Peninsula is early evidence that President Joe Biden is shifting America's approach to alliances in Asia and beyond. It shows he will cut allies a break to build unity in competition against China and Russia.

President Donald Trump had demanded South Korea pay billions more to keep American troops on its soil. In his view, the United States was getting fleeced by what he suggested were freeloaders masquerading as allies. Initially, Trump insisted the South Korean government pay five time...