Lawmakers pressing for stringent gun-control laws have been leaning on the Newtown, Conn., school shooting as proving their points about everything from magazine size to types of weapons that should be owned.

The overnight murder-suicide tragedy at Quantico, though, spotlights a highly charged debate within the broader gun-control policy push — gun ownership by members of the military as policy makers cast suspicious eyes on their states of mind.

The military promises a lengthy investigation of the Quantico incident, which locked down the Marine Corps base in Virginia from 11 p.m. Thursday through early Friday morning.

One active-duty Marine was found dead in a barracks, and another was found shot to death beside the suspected gunman, who died of a self-inflicted gunshot wound.

“This tragedy, as well as the tragedy in Nevada earlier this week, took the lives of Marines who volunteered to serve their nation,” Pentagon spokesman George Little said on behalf of Defense Secretary Chuck Hagel. “His heart and his prayers are with them and their families. He believes that the legendary strength of the United States Marine Corps will ensure that they are forever remembered.”

This afternoon the Defense Department released its monthly suicide data: 11 potential active-duty suicides for February with three confirmed and eight still under investigation. That’s down from 20 potential suicides in January, with seven so far confirmed.

That brings the 2013 total through February to 10 confirmed suicides and 21 still under investigation, and 156 confirmed suicides with 27 still in the hands of investigators for 2012.

Last December, Rep. Hank Johnson (D-Ga.) and then-Sen. John Kerry (D-Mass.) — citing military suicides — urged their colleagues to include an amendment in the defense authorization bill that would allow military officials to ask service members about their private gun ownership.

“Nearly three quarters of the military suicides that occurred between 2008 and 2010 were committed with a personal firearm,” Johnson and Kerry wrote. “Amending this language would simply reaffirm and clarify the ability of military commanders and those tasked with protecting our service members, who identify someone that may be at risk, to discuss personally-owned weapons and perhaps suggest the safe storage of this weapon in a military facility or even the use of a gunlock. This sensible approach does not attempt to limit an individual’s 2nd amendment rights.”

Proponents of imposing greater gun regulations on members of the military cite a 2010 study that found suicides in the Israeli Defense Forces dropped 40 percent in the wake of a 2006 policy requiring soldiers to leave their weapons on base when going home for the weekend. Still, suicide remained the top cause of death for IDF soldiers in 2012.

“The majority of [suicides] have two things in common: alcohol and a gun. That’s just the way it is,” Gen. Peter Chiarelli, the Army’s former Vice Chief of Staff, told the Christian Science Monitor shortly before he retired last year. “And when you have somebody that you in fact feel is high risk, I don’t believe it’s unreasonable to tell that individual that it would not be a good idea to have a weapon around the house.”

Ironically, the House and Senate both held hearings this week on military suicides.

“The one that I think you can maybe, you know, get your head around a little bit is the factor that at least 10 percent, as we know, in the service have perhaps access to guns at a greater level than in the general population,” said Rep. Susan Davis (D-Calif.), ranking member on the House Armed Services subcommittee on Military Personnel, at a Thursday hearing. “And the fact that we have the literature indicating that restricting access to means — firearms, of course — is an effective strategy for preventing suicides.”

Jacqueline Garrick, acting director of the Defense Suicide Prevention Office, said the majority of suicides “were completed by Caucasian males below 29, enlisted and high-school educated. In some cases, relationship, legal or financial issues were present.”

“Service members primarily used firearms and died at home,” she continued. “They did not communicate their intent, nor did they have known behavioral health histories. Less than half had deployed and few were involved in combat.”

Garrick told the committee that about 75,000 gun locks have been distributed through a Safe at Home program and said they’re in the process of working with the defense reauthorization that “just gave us some really good clarifying language on who can, when can you ask about personally owned firearms, ammunition and other weapons.”

“And so, we are working on a guidance for that so that we can get that information out to the services and make sure that everybody, that the clinicians as well as the commanders, are tracking that on what you can do,” she said. “So, I think, that was an important step for us.”

Chairman Joe Wilson (R-S.C.), though, was not so much on the train of thought that firearms ownership kills soldiers as sequestration might.

“Unfortunately, in addition to the hardships of military service, our service members are subject to the same pressures that challenge the rest of society,” he said. “…I’m deeply concerned about the uncertainty of sequestration and the coming budget challenges, how that will affect our service members and their families.”

Earlier this month, the Department of Veterans Affairs announced it wouldn’t comply with New York’s new Secure Ammunition and Firearms Enforcement Act that requires mental health professionals to report those they believe may hurt themselves or others for the purpose of taking away that person’s weapons.

“Federal laws safeguarding the confidentiality of veterans’ treatment records do not authorize VA mental-health professionals to comply with this NY State law,” VA spokesman Mark Ballesteros said.

Last Congress, Senate Republicans failed to get language in the defense bill that would have stopped the Veterans Affairs Department from putting the names of vets deemed too mentally incompetent to handle their finances into the National Instant Criminal Background Check System to prohibit them from buying or owning a gun.

“All I am saying is, let them at least have their day in court if you are going to take away a fundamental right given under the Constitution,” Sen. Tom Coburn (R-Okla.) said.