To some extent, the AIIB's popularity reflects the frustration with the stalled reforms at the World Bank and IMF. The US, or the US Congress to be specific, bears the foremost responsibility for blocking the IMF reform that has been approved by the rest of the world to improve governance and give emerging economies a bigger say.

For this reason, a more positive attitude by the Obama administration towards the AIIB could help ease some of worldwide frustration.

But the AIIB, even with China being the largest shareholder, is really meant for infrastructure financing, not geopolitical jostling, as it appears in the eyes of some US politicians.

Obama angered many Chinese last year by calling China a free rider, but when China tries to shoulder more responsibility, the US has again been picking fault, based on sheer speculation.

The US' attempts in the past months to coerce its allies not to join the AIIB smacks of its Cold War mentality, and is not constructive to today's globalized economy. In this sense, a new US attitude toward the AIIB would help to prove that it does not seek to curtail China's rise.

Despite Washington's earlier hostile attitude, Chinese officials have expressed in the past days that both China and the AIIB would welcome the US being a member, but added that it's okay if Washington needs more time.

It's time for Washington to discard its old mentality that clearly has been discarded by the rest of the world.

The author, based in Washington, is deputy editor of China Daily USA.