Ever since the end of the Second World War, the United States (US) has been the main anchor for the liberal international trading system. Its policy agenda, including non-liberalising measures such as tightening intellectual property rights, has frequently been controversial.

But there are few major initiatives in trade policy that do not involve the US playing a central role.

This tradition is under threat from US President Donald Trump’s administration, which has abrogated the US’ participation in the Trans-Pacific Partnership (TPP), a signed (but not yet ratified) deal with 11 other Asia-Pacific economies.

His officials, including Commerce Secretary Wilbur Ross, have stated instead their preference for one-on-one deals, where the US can address its misguided ambition to use trade policy to reduce bilateral current account deficits.

The initial reaction in the other TPP countries to the US’ withdrawal was one of shock and disappointment. Japanese Prime Minister Shinzo Abe said the agreement would be “meaningless” without US participation. But now Japan, the second-largest economy in the pact, has changed its mind and suggested the other TPP nations go ahead without the US.

There are obvious problems with this course of action. Since the US is bigger than all the other TPP economies put together, its absence will heavily reduce the impact of the deal. Taking America out of the TPP is not as simple as deleting it from the agreed text: It will require a comprehensive revision of the agreement.

And opening up the deal, particularly without the US pushing for far-reaching provisions, could mean it being painfully renegotiated and perhaps weakened.

Still, Japan’s attitude deserves praise. Initially, Mr Abe became involved in the TPP largely to force domestic reform, particularly in agriculture, with the promise of more access to the US market as a trade-off. If he is prepared to do the former without the latter, it shows how the domestic debate in Japan has shifted.

Second, if the US is not prepared to show leadership in maintaining and extending the trading system in Asia, it would be a welcome development for Japan to take up at least some of the running in its absence.

There is often overheated talk about China replacing the US as the trade policy hegemon in Asia, including through the proposed Regional Comprehensive Economic Partnership (RCEP) agreement. This ignores the fact that, as the limited content of the RCEP shows, China is interested in little more than reducing goods tariffs to help its exporters.

Deals led by Japan — and including advanced economies such as Australia and New Zealand — will at least address much more sophisticated issues relevant to modern commerce, including services and regulation.

As for the US, it should be careful that its withdrawal from the TPP does not leave it isolated and allow others to usurp its role. Access to the US market is still a powerful lure, but if Tokyo can put together meaningful deals in the region, it will feel less compelled to sign a bilateral deal with the US.

In the meantime, a deal between Japan and the EU is well advanced, and in any case, European regulations have a way of creeping into trading partners’ economies even without a formal trade deal.

Japan’s TPP initiative shows that updating the trading system in Asia is not a failed project. Secondly, keeping the TPP alive would mean that the US cannot count on being able to impose its will through a series of bilateral deals as long as a regional alternative exists.

And Mr Abe may not have given up all hope of finding a way to coax the US back into the fold. There is, after all, always life after Mr Trump. FINANCIAL TIMES