Secretary of State nominee Mike Pompeo told senators Thursday he would not resign from the Cabinet if President Trump were to fire special counsel Robert Mueller.

“My instincts tell me ‘no,’” Pompeo, currently the CIA director, told the Senate Foreign Relations Committee when asked if he would resign over a Mueller firing. “My instincts tell me that my obligation to continue to serve as America’s senior diplomat will be more important in increased times of political domestic turmoil.”

The question, from Sen. Chris Coons, D-Del., was one of several that Democrats asked Pompeo about Mueller's investigation into Russia's election meddling. Others were about reports that Trump appealed unsuccessfully for Pompeo and National Intelligence Director Dan Coats to intervene with then-FBI Director James Comey in March 2017.

Pompeo declined to answer questions about that conversation, though he confirmed that he has been interviewed by Mueller and cooperated with all related investigations.

“I’ve done it with as much thoroughness, as much depth, as much alacrity as our organization could achieve,” he said told Coons.

Pompeo may need Democratic support to win confirmation from the Senate. Republicans hold a 51-49 majority, but Sen. Rand Paul, R-Ky., has announced his opposition to the nomination, and Sen. John McCain, R-Ariz., has been absent for brain cancer treatments, which means the nomination can't lose any more GOP support if all Democrats oppose him.

But Pompeo stuck to his answer that he would remain in his post even if Trump goes after Mueller.

“This wouldn’t be the first time that there’s been enormous political turmoil,” Pompeo said to Coons. “My recollection of the history is that previous secretaries of state stayed the course, continued to do their work, continued to do the requirements — statutory and constitutional — that they had. Having not given it a great deal of thought, I’m confident that that’s the path that I would take.”

Coons took a collegial tone with Pompeo, even as they discussed the prospect of a resignation or refusal to resign.

“Whether the right course is to resign or to engage and to speak out against it and to counsel against it and to then work to restore the rule of law, we can debate. But I think it’s vital that we have as our chief diplomat somebody who understands our values, as I believe you do,” Coons said. “And who is willing to fight for them even by taking dramatic steps like a resignation in order to signal vigorous disapproval of what the president has done or might do.”

Senate Republicans are increasingly concerned that Trump might fire Mueller, particularly following reports that the FBI had raided the law offices of the president’s private attorney, Michael Cohen. That investigation was not undertaken by Mueller, but rather the U.S. attorney for Southern District of New York, although it was partly a function of information referred to the U.S. attorney by Mueller’s team.

Democrats are also increasingly worried, and Coons urged Pompeo to reconsider.

“I’d urge you to give it some thought,” Coons told Pompeo about the idea of resigning. “Many of us are giving it some real thought and have had to do so for months. And it is regrettable, I think, that we’re in a place where we’re seriously discussing this rather than diving into the policy questions that face us around the world. But I think there are moments when our values and what we do teaches to the world.”