Washington, what are you waiting for?

Welcome Germany! Welcome France! Welcome Italy!

Despite a petulant and cynical Washington, the three leading European powers decided to join the Asian Infrastructure Investment Bank (AIIB) headquartered in Beijing on Tuesday.

The brave yet rational move has laid bare the attractiveness and influence of the AIIB, given the difficulty for those leading EU members to reach a consensus over issues related to China inside their union, where they often kick the can down the road.

It also sends clear signals to the whole world, and particularly to the United States, who is trying to forge an anti-AIIB front within its allies.

Firstly, in an international community bound together by interdependence, win-win cooperation, rather than self-concerned fulfillment, is the order of the day.

The AIIB is by no means a zero-sum game. It serves no one's appetite for hegemony or dominance. Rather, it is a reciprocal, efficient and inclusive platform where member states could seek mutually beneficial cooperation.

Secondly, the AIIB is a helpful and somewhat indispensable complement for the existing international and regional lending bodies controlled by the U.S., such as the International Monetary Found (IMF) and the Asian Development Bank (ADB), for the sake of their inadequate efficiency and capacity.

Frankly speaking, the IMF and ADB alike can not neatly meet the enormous yet still growing need of infrastructure investment in Asia. Against that backdrop, the founding of the AIIB could help them to cope with the growing need in a better way and inject direly needed competition into the Washington-monopolized lending system.

By joining the AIIB, Germany, France and Italy have actually booked their shares in Asia's booming investment.

Thirdly, holding sour grapes over the AIIB makes America look isolated and hypocritical.

The joining of Germany, France, Italy as well as Britain, the AIIB's maiden G7 member and a seasoned U.S. ally, has opened a decisive crack in the anti-AIIB front forged by America.

As more and more Western countries mull over joining the China-led lending body, the U.S. will feel lonelier if it continues to be a holdout.

Moreover, accusing the AIIB of lacking transparency while holding out from it doesn't strengthen the moral high ground of Washington, as the best way to cure the "self-claimed flaw" is working inside the new Asian financial body, instead of just carping from outside.

It makes Washington more hypocritical when it comes to the "China free rider" allegation initiated by U.S. President Barack Obama in an interview with the New York Times last August, during which Obama blamed China for not taking more international obligations.

However, when China moves in that direction, as it is doing with the AIIB, the America seeks to boycott it.

For all that, the AIIB has clearly demonstrated China's will to share its development opportunities with the whole world.

Unlike the U.S.-led TPP negotiation which excludes China, the AIIB is open to all interested parties, including the United States.

So Washington, what are you waiting for?