The Trump administration has stopped cooperating with UN investigators over potential human rights violations occurring inside America, in a move that delivers a major blow to vulnerable US communities and sends a dangerous signal to authoritarian regimes around the world. Quietly and unnoticed, the state department has ceased to respond to official complaints from UN special rapporteurs, the network of independent experts who act as global watchdogs on fundamental issues such as poverty, migration, freedom of expression and justice. There has been no response to any such formal query since 7 May 2018, with at least 13 requests going unanswered. Nor has the Trump administration extended any invitation to a UN monitor to visit the US to investigate human rights inside the country since the start of Donald Trump's term two years ago in January 2017. [This] marks a stark break with US practice going back decades. Though some areas of American public life have consistently been ruled out of bounds to UN investigators - US prisons and the detention camp on Guantnamo Bay are deemed off-limits - Washington has in general welcomed monitors into the US as part of a wider commitment to upholding international norms. Jamil Dakwar, director of the American Civil Liberties Union's human rights program, said the shift gave the impression the US was no longer serious about honoring its own human rights obligations. The ripple effect around the world would be dire.