At a time when pressing matters of finance and geopolitics dominate the diplomatic agenda, issues of religious freedom hardly ever surface in exchanges between the world’s powerful countries. High-level debates about freedom of belief are so relatively unusual these days that they stand out.

Leaders and governments do sometimes speak out when under pressure from domestic constituencies. In May, Donald Trump took Turkey’s Recep Tayyip Erdogan to task over the incarceration of an American pastor, Andrew Brunson; the preacher’s fate was of concern to Trump-voting evangelical Christians. And last month, Germany’s ambassador in Beijing (clearly with Berlin’s approval) made an eloquent protest about the treatment of the Catholic church in China. At the heart of the case was the apparent abduction by officialdom of a bishop who was elevated by Rome last October. Although the German foreign ministry was acting in the name of general principles, the country’s 24m Catholics (about 30% of the population) clearly have an interest in the fortunes of their Chinese co-religionists, and want their government to act accordingly.

Every so often, though, a voice is heard that serves no obvious political constituency. Such was this week’s strong statement by the United States Commission on International Religious Freedom (USCIRF) on the treatment of the Muslims in northwestern China, particularly during the holy month of Ramadan which has just ended. The Xinjiang region (pictured), home to the Uighurs who are a Turkic people, has historically been the main stronghold of Islam in China. But it is not an easy place to practise that faith. In the words of the USCIRF chairman, Daniel Mark:

The Chinese government has taken unprecedented steps to trample on the religious freedom of Uighur Muslims particularly during Ramadan. Chinese Communist Party officials were assigned to live in the homes of Uighur families in Xinjiang to prevent them from fasting and praying. This new level of control is yet another example of the Chinese government’s unacceptable repression of Uighur Muslims. We call on Beijing to abide by its international human rights commitments and cease its harassment of religious communities.

According to Uighur exile groups, many people in Xinjiang were fined heavily or subjected to programmes of “re-education” for refusing to eat during the daytime, as Chinese authorities were pressing them to do. In April, it was reported that hundreds of Uighur Muslims had been detained by the authorities as they returned from pilgrimage in the Middle East. In another repressive measure, many standard Muslim names may no longer be conferred on babies.

The USCIRF is an advisory body, jointly appointed by the White House and Congress, with a mandate to study and call out abuses of religious freedom. The State Department is free to accept or turn aside its recommendations on which lands should be designated as “countries of particular concern” or egregious violators. But the commission’s pronouncements do carry weight: enough to seriously annoy countries like India which find themselves being investigated.

And in an age of populism, nativism and political expediency, there is something magnificently improbable about a prestigious US agency lobbying for the rights of Muslims in China.