MARINE CORPS BASE QUANTICO, Virginia -- When the Marine Corps' top leaders were summoned to Capitol Hill two years ago to explain how they were addressing a major social media scandal, Sgt. Maj. Ronald Green called it one of the lowest points of their careers.
"We never stopped to think for one second that we had male Marines doing this to our females, to our family, to the ones we love," Green, who recently retired, told Military.com after a leadership panel here.
Green was serving as sergeant major of the Marine Corps when an explosive report detailed how hundreds of male Marines and veterans were using a Facebook group called Marines United to share nude photos of their female colleagues online without permission. It was a major scandal for the service, which has struggled to address high numbers of reports of sexual assault and other gender issues in the ranks.
Green and then-Commandant Gen. Robert Neller were called on to testify about how they planned to address Marines' mistreatment of women online and problems in the service's culture.
Now, with members of Congress concerned about a potential rise of racism and other extremist ideologies in the ranks, Green said leaders must stay plugged into what's happening on Facebook, Instagram, Twitter and other online spaces.
Social media, he said, gives "a voice to those who yesterday didn't have a voice." Before Marines United, Green said the Marine Corps didn't have a firm grip on what was going on with social media. They'd see some problems here and there, fix them, and then refocus somewhere else.
"Then we found out how much [social media] mattered," he added. "I'd tell General Neller all the time, 'Remember, everyone has a megaphone today, and they're not afraid to push that button either above ground or underground.'"
The Marine Corps has opened several investigations in recent months into troops' alleged racist social media posts.
Last month, a reservist lost a rank after he sent a photo of Marines making a swastika shape with their boots to Max Uriarte, the creator of the "Terminal Lance comic. Uriarte is Jewish.
In May, a Hawaii-based lance corporal was slapped with an other-than-honorable discharge after he admitted to advocating supremacist ideology online. The infantry Marine had shared a photo of a swastika, a meme with the n-word, a post that encouraged violence against women, and a joke about shooting feminists.
And in February, a command in California opened up another investigation into a Snapchat video that showed two Marines in charcoal face masks making racist comments.
When asked how the Marine Corps is combating service members sharing racist posts on social media, Sergeant Major of the Marine Corps Troy Black said he isn't "tracking any of that."
"Anybody that's found to have misconduct on social media once the investigation is complete and the results of those investigations are known, then proper action will always be taken," Black said. "I think the Marine Corps policy right now on social media is pretty clear -- I won't add or subtract from that."
Several other military services have also been grappling with investigations into racist online or public posts and statements.
Earlier this year, a Coast Guard officer was reprimanded for making a white-nationalist symbol during a live TV spot about hurricane relief efforts. And two months later, the military launched an investigation into five troops' possible ties to a white-nationalist organization called Identity Evropa.
All the services could face new rules about how they're tracking problems with white nationalism and other extremist ideologies in the ranks. Lawmakers introduced an amendment into the defense spending bill that could require them to report to Congress within six months what they're doing to identify those problems.
That comes as experts -- and some retired military officers -- warn about the rise of homegrown extremist ideologies.
After he was named the next commandant, Gen. David Berger told Military.com in an interview at the Pentagon that leaders must continuously educate their Marines, so they understand what is and is not acceptable in the Corps.
"We should never assume that a 17-year-old Berger or 18-year-old Berger coming out of high school knows what's appropriate and not for the Marine Corps," Berger said. "In 13 weeks [of boot camp], you can cover a lot of ground, but there will be a level of detail where perhaps you need either more education or more reinforcement to what's appropriate."
Green agrees, and said those conversations need to happen as soon as prospective Marines drop into recruiting offices.
"That's where the conversation starts," the former sergeant major of the Marine Corps said. "If you think you're going to be a part of this Marine Corps family, then you need to have your social, your emotional, your physical, your mental and your spiritual life in order."
And as leaders rise through the ranks, Green said it's critical they stay in tune with societal issues that could affect Marines.
"Anything that happens with technology and innovation, we need to be aware of, especially if it's going to affect the people -- the most important resource we have," he said.