Should Japan join the China-led multilateral financial initiative, the Asian Infrastructure Investment Bank (AIIB)? The question arises whenever the bank welcomes important new members — Britain, Germany, France and Italy last year and, most recently, Canada. Despite China's courting and Japan's intense domestic debates, Tokyo, along with Washington, has been holding out and betting on a rival initiative — the Trans-Pacific Partnership — to maintain its role in regional economic cooperation.

Nonetheless, America introduced a wild card — Donald Trump's victory in the presidential race — that basically declared the death of TPP. It's not just Trump's win, either. Brexit, Italy's referendum failure, and the rising populist backlash against globalization and free trade more generally all point to a dimmer future for global and regional economic integration. Against this backdrop, China and Japan need to take leadership and jointly construct a positive agenda to maintain the momentum of such integration. Tokyo's reconsidering its AIIB holdout could be a step in the right direction.

Tokyo did not jump on last spring's AIIB bandwagoning because of deep concerns, which centered around the bank's operation. Unlike the Asia Development Bank (ADB), which holds a clear goal of poverty reduction, Tokyo questioned the obscurity of AIIB's vision. Japan wondered, in Foreign Minister Fumio Kishida's words, "Whether there will be added value from creating a new international institution in addition to the existing international development financial institutions?"