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

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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.

Hegseth’s remarks generated a barrage of praise and condemnation. And they raised a question:

“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.

The military services have struggled for years to meet recruiting goals, facing stiff competition from companies that pay more and offer similar or better benefits. And a growing population of young people aren’t interested in joining or can’t meet the physical, academic and moral requirements.

Removing women from contention for jobs, said Manning, could force the services to lower standards to bring in more men who have not graduated high school, have criminal records or score too low on physical and mental tests.

Lawmakers are divided on Hegseth’s views.

“Where do you think I lost my legs, in a bar fight? I’m pretty sure I was in combat when that happened,” snapped Sen. Tammy Duckworth, D-Ill., in an CNN interview last Wednesday after Trump’s selection was announced.

Duckworth, who flew combat missions in Iraq and lost both legs when her helicopter was hit, added, “It just shows how out of touch he is with the nature of modern warfare if he thinks that we can keep women behind that sort of imaginary line.”

Sen. Lindsay Graham, R-S.C., praised Hegseth and said the reality is that certain military jobs “just need brute strength. ” But he added, “women have served incredibly well, honorably in combat roles, and I don’t think that policy is going to change, but we’ll leave it up to him.”

Steven Cheung, a spokesman for the Trump transition, said Hegseth has dedicated his life to supporting American troops and his country, and cited his service in Iraq and Afghanistan and two Bronze Stars.

“He is an incredibly tough and smart candidate that will fight to put America first. With Pete as our secretary of defense, America’s enemies are on notice and our military will be great again,” Cheung said.

Others, including a number of military women, disagree with Hegseth’s views on female troops in combat.

“Pete Hegseth’s views on women in the military are outdated, prejudiced, and ignore over 20 years of evidence proving women’s effectiveness in combat roles,” said Erin Kirk, a Marine Corps combat veteran. She said women have served honorably and effectively as pilots, logistics personnel, intelligence operatives and infantry grunts.

“Hegseth’s stances aren’t just regressive, they pose a direct threat to the Department of Defense’s readiness, and by extension, to our national security,” Kirk said.

Hegseth has said he is not suggesting women should not be combat pilots, but that they should not be in jobs such as SEALs, Army Rangers, infantry, armor and artillery where “strength is a differentiator.” He insists the military lowered standards to get more women into combat roles. The services have said they did not decrease the standards for any of the combat jobs.

Hegseth’s view on women in combat reflects much of the debate over the past nine years, in the wake of then-Defense Secretary Ash Carter’s order in late 2015 that the military open all military jobs to women. That change followed three years of study and wrangling and was a formal recognition that thousands of women had served — and many were wounded or killed — on battlefields in Iraq and Afghanistan.

Carter said then that the military could no longer afford to exclude half the population from high-risk military posts and that any man or woman who meets the standards should be able to serve.

The Marine Corps was fiercely opposed to the idea and sought an exemption, which was denied. Special operations forces in surveys done in 2015 and more recently, said women did not have the physical or mental strength to serve in elite commando units and doing so could hurt the units’ effectiveness and lower the standards.

The numbers are small, but women have passed the grueling qualification courses to join special operations units. Two are serving as Navy Special Warfare combat crewmen, three in Air Force special operations units and fewer than 10 are Green Berets.

More than 150 women have completed the Army Ranger course, and several hundred more are serving in Army Special Operations Command jobs such as civil affairs, psychological operations and helicopter pilots, including in the 160th Special Operations Aviation Regiment.

And, more broadly, thousands of women have served or currently are in jobs that until 2015 were male-only, including in Army and Marine Corps artillery, infantry and armor units.

Lowering standards has been a key talking point for Hegseth.

By opening combat slots to women, “we’ve changed the standards in putting them there, which means you’ve changed the capability of that unit,” Hegseth said in the podcast interview.

Both male and female troops were outspoken since the start of the debate in their opposition to any reduction in standards for the jobs.

Manning, the Navy captain, said Hegseth is conflating two separate issues on standards.

The services do adjust requirements for the annual physical fitness test according to a service member’s age and gender, but they do not adjust the requirements for specific jobs.

Every job, said Manning, “has a set of occupational standards that have to be met.” Those range from physical strength and capabilities to things such as color blindness or academic testing. “Those, by law, have got to be gender neutral. And they are, and they have been for years,” she said.

Monica Meeks, who lives near Fort Campbell, Kentucky, was in the Army for 20 years and served in Iraq. She said she served with women in a variety of infantry jobs, including the first female platoon sergeant in the 18th Airborne Corps.

“When people say women shouldn’t serve in a combat zone, like an IED (improvised explosive device) can happen at any time. So there is no front line in these wars in Afghanistan and Iraq,” Meeks said.