Few people inside President Obama’s Pentagon have been more closely associated with the progressive changes in the military over the past eight years than Navy Secretary Ray Mabus.

And now, on the eve of his departure, with an incoming administration that has questioned his signature achievements such as integrating women into combat units, Mabus is offering a final passionate argument for the next administration to hold the line.

Mabus, the soft-spoken former gG​overnor of Mississippi, was one of the loudest voices in the department calling for the 2011 repeal of the Don’t Ask, Don’t Tell policy that made gay service members keep quiet about their sexual orientation or face discharge. More recently, he was a forceful advocate for the Pentagon's decision last year to integrate women into combat roles in both the Navy and the Marine Corps.

Yet the women in combat policy may be in question now. The presumptive incoming secretary of defense has been on the other side of the argument. Retired Marine Gen. James Mattis has spoken out against integrating women into combat roles. Mattis has said that while he believes women could meet the physical standards, it is still improper to put women into the "atavistic primate world" of close-quarters fighting.

"It would only be someone who never crossed the line of departure into close encounters fighting that would ever even promote such an idea," Mattis wrote in a book published last year, "Warriors & Citizens."

Mabus, speaking to reporters Wednesday, offered a full-throated defense of the progressive movement he’s led inside the Navy, arguing that removing women from combat roles or rolling back Don’t Ask Don’t Tell would make the military a less effective fighting force. Here are his remarks:

"You make the decisions you think are right at the time and will strengthen the Navy and Marine Corps. We have a better force because we are more diverse.

Of course you could roll it back; you can roll anything back. But if you do, you will make us weaker. If you do, you will be saying that because of what you look like, or your gender, or who you love … even though you qualify for the job – even though you met every qualification – we're going to keep you from doing it. That's no America, that's not who we are.

How can you deny someone the honor of defending this country when they meet the standards? You are not lowering the standards, you are not doing it to be diverse you are doing it to be better. So if you want to go backwards. If you want to make us a weaker force, do it. But you will be a weaker force if you do that.

I'll finish with a story:

I was in Manaus, Kyrgyzstan, where everyone going in and coming out of Afghanistan passed through – this was a few months after the repeal of Don't Ask Don't Tell. I did an all-hands call with about 800 sailors and Marines.

Afterwards a first class petty officer, a corpsman, he had just finished his third combat tour with the Marines. And he came up and he thanked me for pushing for the repeal of Don't Ask Don't Tell, and he said he was gay and that he was scared to death his entire time in the Navy that he was going to be found out and forced to leave.

Now here's a guy who had just done three combat deployments, risked his life time after time to go to Marines' aid but his biggest fear was that he was going to be kicked out of the military for who he was and who he loved. Now how wrong is that? And how bad is that for our force? If we didn't have him we would have been a weaker service.

So yes, they can roll it back, you can always roll things back. But you will make us a weaker fighting force if you do. If that's your aim, then go ahead. But that is what will happen."