In foreign policy , Mr . Koizumi has exhibited the same leadership that has characterized his economic and political initiatives . In the country ’ s largest operations since World War II , Japan dispatched non - combat forces to Iraq . In response to the growing threat from North Korea , Japan has participated with the United States in missile - defense activities . Even though China and Japan have become each other ’ s largest trading partner in recent years , Mr . Koizumi has left no doubt that he believes Japan ’ s alliance with the United States is paramount .