The United States has left an empty chair at a key United Nations human rights review for the second year running, becoming the only U.N. member state ever to do so, NPR reported from Geneva.

The review, known as the universal periodic review, is meant to be universal. Each state is reviewed every four to five years by fellow member states, with the aim of ensuring that every country, however powerful, undergoes a peer review of its human rights record. Diplomats from countries under review take part, and civil society groups are allowed to submit evidence too. Several made the trip to Geneva, led by the American Civil Liberties Union.

Jamil Dakwar, the ACLU's human rights director, told journalists that the current U.S. administration was continuing to violate human rights "unabashed," citing the treatment of immigrants, student protesters and the LGBTQ community as examples. He said the U.N. must hold the United States accountable, warning that the Trump administration wanted to "dismantle human rights." In a written response, the State Department pointed out that Washington had already formally withdrawn from the U.N. Human Rights Council, accusing it of "pushing anti-American rhetoric," NPR reported.

Leaving the council is not the same as leaving the review

Leaving the council, which has 47 elected members, does not mean the United States can easily get out of the review process, which is obligatory for all 193 U.N. member states. Human rights groups see Washington's stance as part of a pattern of disengagement, pointing to U.S. sanctions on the International Criminal Court and the decision to leave the World Health Organization.

The U.N. has few sanctions against a country that does not cooperate. Israel skipped one review in 2013 in protest at what it said was anti-Israel bias, but returned nine months later after the U.N. rescheduled. Until this no-show by the United States, no country has ever failed to turn up twice, NPR reported. Rights groups would like the U.N. to hold the review anyway and take evidence about alleged violations in the United States. Member states had already drawn up a list of questions for Washington's diplomats, including questions about the use of the death penalty and restrictions on abortion.

U.N. insiders fear that holding the review when there is no one to answer those questions could set a risky precedent. Even authoritarian regimes such as North Korea take part. If the U.N. allows a review to go ahead without U.S. participation, it could encourage other member states to stay away, leaving rights groups to present their evidence, as one put it, "in a vacuum." For now, the U.N. has decided to postpone deliberations about how to react until early next year. In the meantime, a process regarded as a last resort for victims of human rights violations is not available to U.S. citizens. It is, one rights activist said in Geneva, "a crisis of accountability."