British Defense Secretary Gavin Williamson recently announced that the Royal Navy would be conducting a South China Sea Freedom of Navigation Operation (FONOP) after its visit to Australia later this year. His statement also contained a rare full-throated specific endorsement of U.S. FONOPs in the region. “We absolutely support the U.S. approach on this, we very much support what the U.S. has been doing,” he commented, adding, “The U.S. can only concentrate on so many things at once. The U.S. is looking for other countries to do more. This is a great opportunity for the U.K. and Australia to do more, to exercise leadership.”

I am sure that Williamson’s comments were warmly welcomed in Washington: It seems clear that current U.S. policy seeks to encourage or even push allies to conduct South China Sea FONOPs. During his recent joint appearance with Australian Prime Minister Malcolm Turnbull, President Trump said he would “love for Australia” to join U.S. FONOPs in the South China Sea. Turnbull did not rule out such FONOPs, and neither did Australia’s foreign minister Julie Bishop during a recent television interview. This not-so-subtle U.S. pressure is also highlighted by the nomination of U.S. Pacific Command chief Adm. Harry Harris (a China hawk) to the position of U.S. ambassador to Australia.

In the past, the U.S. has also sought to encourage FONOPs in the South China Sea by the Japanese Maritime Self-Defense Forces. In 2016, then-French Defense Minister (and current Foreign Minister) Jean-Yves Le Drian has expressed interest in bolstering Europe’s maritime presence in the South China Sea. India, a member of the emerging “Quad” in the Indo-Pacific (along with Japan, the U.S. and Australia) is an obvious candidate to conduct FONOPs as well.

A skeptic might ask: How will FONOPs by other countries help deter Chinese expansionism in the South China Sea if U.S. FONOPs alone have not done so? The Chinese state media is already sneering at the no-longer-mighty Royal Navy daring to interfere in the region. The U.S. does not lack naval firepower; what it has largely lacked, until now, was action by other countries demonstrating support for its views on freedom of navigation rights in the South China Sea. Britain is about to provide such tangible support, and as a bonus, it is also calling on Australia to do the same.

Officially, FONOPs are merely expressions of a country’s views about its rights under international law. But China’s increasingly harsh public criticisms of FONOPs have actually transformed these operations into a useful tool for demonstrating a country’s willingness to suffer Chinese disapprobation. That is certainly what FONOPs have become for the United States.

While the U.S. has shown its willingness to irritate or even anger China, up until now, countries like Britain and (especially) Australia have not. This reticence is probably due to those countries’ strong economic ties with China. Getting those countries to join FONOPs will bolster the U.S. view of international law, but, more significantly, it will bolster confidence that countries other than the U.S. are willing to defy China on this sensitive point. That is why it will be important to convince Japan and India to join the FONOP party at some point as well, in order to demonstrate those countries’ confidence in their ability to withstand withering Chinese criticism and anger.

FONOPs, even joint FONOPs with other nations, will not by itself roll back China’s expansion in the South China Sea. But more FONOPs conducted by more nations will globalize the dispute beyond U.S.-China relations and make China incur new costs for its policies. Hopefully, they will also cause China to think twice about further regional expansionism.