Ben Emmerson, the United Nations special rapporteur for human rights and counterterrorism, tells Danger Room he’s giving his qualified backing to John Brennan, President Obama’s top counterterrorism adviser and nominee to become CIA director. The endorsement comes at a critical time for both men: Brennan faces Senate questioning on Thursday afternoon, and Emmerson is negotiating access with the U.S. government to its targeted-killing efforts for his recently announced international inquiry into their legality.

It’s an unlikely endorsement. Emmerson, a British lawyer, has put the U.S. on notice that he won’t hesitate to investigate U.S. “war crimes” if he uncovers evidence of them. While Emmerson’s inquiry won’t focus on individuals responsible for any uncovered abuses, Brennan, as a White House aide, presided over the bureaucratic process for ordering suspected terrorists killed.