President Donald Trump’s nominee for defense secretary, Pete Hegseth, has reignited a debate that many thought was settled long ago: Should women be allowed to serve their country by fighting on the front lines?

The former Fox News commentator has made it clear, in his own book and in interviews, that he believes men and women should not serve together in combat units. If Hegseth is confirmed by the Senate, he could try to end the Pentagon’s nearly decade-old practice of making all combat jobs open to women.

“I’m straight up just saying we should not have women in combat roles. It hasn’t made us more effective. Hasn’t made us more lethal. Has made fighting more complicated,” he said in a podcast hosted by Shawn Ryan on Nov. 7. Women have a place in the military, he said, just not in special operations, artillery, infantry and armor units.

“Who’s going to replace them? Men? And we’re having trouble recruiting men into the Army right now,” said Lory Manning, a retired Navy captain who works with the Service Women’s Action Network.