Numerous concerns have been raised about Mike Pompeo, President Trump’s nominee for secretary of state. Though the US Senate confirmed him as  the Central Intelligence Agency director, albeit with significant objection, his new role would be much different and raises a host of new concerns.

One is the influence he could exert over US overseas “rendition” policy – how the US handles the transfer of people from US custody to the custody of other governments or non-state armed groups abroad. US rendition practices in the years following the September 2001 attacks resulted in numerous abuses. In addition to unlawfully detaining and torturing scores of men in US custody, the US also sent an unknown number to countries where they faced torture — and many indeed were tortured –, violating the Convention against Torture, to which the US is party.

The Obama administration refused to take as strong a position as it could have on whether the US is legally bound by that treaty’s  prohibition on transferring people to places where they face a substantial risk of torture when that transfer takes place outside of US territory. Its position remained shrouded in secrecy.

Only after it released an unclassified portion of US overseas transfer policy as part of a summary of its legal positions at the end Obama’s second term did it become clear that it had adopted the George W. Bush administration’s position that the US is not legally bound by the treaty’s transfer provisions when those transfers take place outside the US. However, it did state that the US applied convention obligations as a matter of policy to all transfers regardless of location.

The position is contrary to international law and went against the advice of many key senior Obama officials, including the State Department legal adviser, Harold Koh. In 2013 Koh wrote a 90-page memo urging the administration to reject the “untenable” legal position that the US is not legally bound by this treaty provision concerning a transfer outside of US borders.

Given the integral role the State Department plays in these transfers, along with Pompeo’s past expression of support for CIA torture and his apparent frustration with laws barring it, senators should make this issue a major focus of his confirmation hearings. Does he consider the US to be bound by the convention’s transfer provisions outside the US? If not, will he commit to apply the convention’s standards on transfer as a matter of policy as the prior administration did? If so, how will he ensure this policy is enforced? Will he ensure that the US never transfers anyone from US custody to a government or non-state armed group when they are likely to face torture?

Though senators questioned Pompeo about his attitudes on torture during his CIA confirmation hearing, those questions focused mostly on whether he would abide by a 2015 law enacted after he made his views in support of the CIA’s use of so-called “enhanced interrogation techniques” known. During his confirmation hearing, he did recognize the validity of that 2015 law and promised to respect it but in written follow-up questions and during interviews while CIA director, said he would look at the possibility of revising that law or finding ways around it if he found that US interrogators were unduly constrained.

There are strong safeguards against revising the 2015 law, which requires US interrogators to use only those techniques listed in the US Army Field Manual. The manual, which has its flaws, explicitly bans many unlawful practices the CIA used in the past, such as waterboarding, and torture more generally. Any revisions would have to be approved by Defense Secretary James Mattis, an outspoken critic of the use of torture, who at one point seemed to have convinced Trump that using it was ineffective, if not necessarily wrong. This time around, senators should focus their questions on the US overseas transfer policy given how much influence on these matters Pompeo could exert at the State Department. According to former senior State Department and National Security Council officials, the State Department is deeply involved in negotiating these transfers, determining their legality and appropriateness, and ensuring certain safeguards are in place when they do occur.

These questions are more important than ever given the shifting dynamics of US military operations. The US is engaged in major military operations around the world yet it has drastically reduced its detention operations in these locations. It relies more than ever on partner forces that detain and interrogate people in their custody. Just days ago it was revealed that the US military is spending about $1 million to help detain thousands of Islamic State fighters and their family members in makeshift camps run by Kurdish militias in northern Syria.

The only new detainee the Trump administration says it is holding is an unnamed American citizen in Iraq. This detainee requested a lawyer but the US refused to provide one until a court ordered it months later, after the American Civil Liberties Union sued to represent him. It also sought to transfer him to Saudi Arabia even though it has a well-known record of torture. In Yemen, US interrogators have questioned detainees in secret prisons run by the United Arab Emirates (UAE) and UAE-backed Yemeni forces where torture is widespread, and in another undisclosed location where the detention conditions were not known.

In this environment, the line between where partner custody ends, and US custody begins, as well as what constitutes a transfer to another government’s custody, should be closely watched. Pompeo’s expressed frustration with laws banning torture, the leading role the State Department plays in overseas transfers, and the limited domestic legal constraints on them, should make these issues and questions an important focus of Pompeo’s upcoming nomination hearing.

Photo: A Casa 235 turboprop plane with registration number N168D at Ruzyne Airport April 8, 2005 in Prague, Czech Republic. The plane has been alleged to be affiliated with the U.S. government’s rendition operations in the years following 9/11. Pavel Horejsi / Getty