Gina Haspel’s morally indefensible role in the CIA’s torture program makes her unqualified to be the new CIA director. What’s worse, if confirmed as CIA director, she would be serving a president who has promised “to bring back waterboarding and  . . . a hell of a lot worse.”

But there is another important reason for senators to oppose her nomination—her leadership could create potentially insurmountable problems for the CIA to perform one of its core functions: cooperating with foreign governments, and its European allies in particular.

In 2002, Gina Haspel ran the CIA’s secret prison in Thailand, during which time Abd al-Rahim al-Nashiri was waterboarded there. Then, in 2005, Haspel was involved in the cover-up of that and other torture incidents when she drafted an order to destroy videotapes of CIA interrogators repeatedly waterboarding detainees. She did this notwithstanding a U.S. federal court order issued the previous year requiring the CIA to produce or identify records relating to detainee ill-treatment. These publicly known facts are but a glimpse of what was her much larger, and still secret, role in the CIA.

These are reasons enough for senators to reject her nomination. But if they need another reason, they should consider the fact that key U.S. allies may be unwilling to cooperate with a CIA that has as its head a person who both oversaw torture and has so little respect for the rule of law.

In 2014, our organization, the Open Society Justice Initiative, won a case before the European Court of Human Rights against Poland for hosting a secret CIA “black site” prison where the United States held al-Nashiri and subjected him to torture, such as stress positions that nearly dislocated his arms, mock executions, and threats of his mother and family being brought in to be sexually abused in front of him. (We also brought a second case on his behalf against Romania, which is pending before that court).

The court held that Poland had violated its human rights obligations by collaborating with the CIA in secretly detaining and torturing al-Nashiri, and by assisting the CIA in transferring him from Poland despite the risk of further torture, secret detention, and the death penalty following an unfair trial in Guantánamo Bay. The judgement stands as a warning to all other Council of Europe member states who might entertain such collaboration in the future.

Foreign government cooperation is integral to many CIA operations today. To assuage senators concerns about this, Haspel might try to distance herself from the torture and cover-up that taints her record. But that distancing would hardly be credible: with her past of overseeing and covering-up torture and the president’s enthusiasm for torture, what is to stop the United States from torturing again?

Haspel’s leadership will make governments nervous about cooperating with the CIA. Indeed, especially in light of the European Court’s judgement, any right-thinking European government will not be able to deny the legal and political risks associated with collaborating with the CIA.  Working with Haspel’s CIA, would mean partnering with an agency whose operations may well feature torture and other human rights violations.

In addition, European states are obligated under the international convention against torture to prosecute torturers. One German rights group has already filed a dossier with the country’s federal prosecutor seeking an arrest warrant for Haspel. Maybe political considerations will mean that the complaint goes nowhere. Nonetheless, German officials would have to think twice before letting Haspel visit, lest she taint them. More generally, European governments will have to explain to domestic constituencies why they would collaborate with a CIA leadership that has demonstrated utter disregard for the rule of law.

Were she to become CIA director, Haspel would undermine the CIA’s ability to forge cooperation with other governments. Senators should add this to the list of reasons to oppose her nomination.