Trade between the world’s two biggest economies has ballooned in recent decades, bringing significant benefits but also perils that have led to calls to rethink the relationship.

Despite the destabilizing effects of his economic and foreign policies, as well as a major election loss, President Erdogan shows no sign of interest in course correction.

The alliance with Japan has been the cornerstone of U.S. security policy in East Asia for decades. Now, Japan’s role in global security is growing as challenges from China and North Korea mount.  …