Looking back as his nearly three-year stint as US ambassador to Japan wraps up this month, Rahm Emanuel doesn’t have a single thing to point to as his top accomplishment.

That’s because whittling that list down would be a difficult task.

As envoy to the United States’ key partner in Asia, the former congressman, White House chief of staff and Chicago mayor oversaw arguably the most consequential shift in the bilateral alliance in decades. From Japan’s plan to double defense spending — a move long urged by Washington — to an agreement to allow US Navy ships to be repaired in Japan, Emanuel helped nudge and sometimes spearhead a number of moves to upgrade ties.