Washington(CNN) Less than a month into the six-month delay set by Defense Secretary James Mattis to review the United States military's policy on transgender service members, President Donald Trump announced that transgender individuals would no longer be allowed to enlist or serve in the military.
"After consultation with my Generals and military experts, please be advised that the United States Government will not accept or allow Transgender individuals to serve in any capacity in the U.S. Military," Trump said in a series of tweets Wednesday morning. "Our military must be focused on decisive and overwhelming victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail."
The transgender military ban, as well as Rep. Vicky Hartzler's failed controversial amendment to cut funding for transgender service members' medical treatments, has sparked renewed debate over transgender personnel serving in the US military.
Ash Carter, the defense secretary under former President Barack Obama, announced an end to the ban on transgender people serving openly in the military in 2016, but allowed for a year-long review process to allow the Pentagon to determine how it would accept new transgender recruits into the military.
While Mattis announced last month that he was delaying the July 1 deadline set by Carter to review the military's policy on allowing transgender personnel, Trump's Twitter announcement made the White House's position known.
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During debate over the Hartzler amendment, Mattis called the Missouri Republican to encourage her to withdraw it from consideration. "We had a good conversation about it," Hartzler said, although she ultimately moved forward with her amendment.
In the aftermath of that battle and following Trump's tweet, lawmakers and LGBTQ advocates are left divided over many of the issues that surround transgender military service, including questions of military effectiveness and readiness, government funding for transition-related surgeries, deployability of transgender service members and the impact on living arrangements and in-unit cohesion.
A 2016 Rand Corporation study commissioned by the Defense Department put the number of transgender people in the military between 1,320 and 6,630, out of a 1.3 million-member force.
Requests for comment from the Department of Defense and the White House regarding the timeline of the military ban and its impact on transgender individuals currently serving were not immediately returned.
Trump's announcement comes after Hartzler made headlines earlier in July for her amendment to the 2018 National Defense Authorization Act, which called for cuts in military funding for transition-related surgeries or hormone therapy treatments.
"Funds available to the Department of Defense may not be used to provide medical treatment (other than mental health treatment) related to gender transition to a person entitled to medical care under chapter 55 of title 10, United States Code," the amendment stated.
Although the amendment was narrowly defeated, 209-214, Hartzler told CNN in a phone interview last week that several absences from Republican lawmakers could have tipped the scales. Six Republicans, including House minority whip Steve Scalise, who is still recovering from last month's congressional baseball practice shooting, did not vote on the amendment. In total, 24 GOP lawmakers and a unanimous Democratic bloc voted against it.
"The vote count would have been different if we had several members who ended up having to be away from their vote at the last minute," Hartzler told CNN. "But it was very close."
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During a press conference Tuesday morning, House Speaker Paul Ryan was also asked about GOP support for the Hartzler amendment.
"As you saw in the NDAA, it didn't have a majority on the floor," Ryan said. "But a majority of our conference is for the Hartzler amendment, ... so the typical tension of an issue like that is occurring."
One of those lawmakers who opposed the measure, Rep. Justin Amash from Michigan, explained his decision in a lengthy Facebook post following the vote.
"The NDAA is an authorization bill for the upcoming fiscal year, which begins on October 1, 2017. Sec. Mattis is expected to present a new policy, if at all, by January 1, 2018. In other words, the Trump administration is asking for only three additional months under the current policy," Amash wrote. "Given the facts, circumstances, and eminently reasonable request from the Trump administration, it was not a difficult decision to vote no on this amendment. After Sec. Mattis announces the DoD's finalized policy, we can discuss the policy with him, evaluate it, and seek changes if necessary."
"With respect to transgender persons, we should focus on the best science, not the political or philosophical opinions of partisans," the Republican lawmaker added.
Trump's latest tweets about the US military's policy on transgender service members have thrust the Hartzler amendment back into the spotlight.
While it remains unclear what a new transgender military ban would mean for the future of Hartzler's attempts to cut military funding for transition-related surgeries, she reacted to Trump's tweet by telling CNN in a statement: "I'm pleased to hear that President Trump shares my readiness and cost concerns, and I'm glad the President will be changing this costly and damaging policy. Military service is a privilege, not a right."
"We must ensure all our precious defense dollars are used to strengthen our national defense," she added.
As part of her amendment, Hartzler claimed that the transition-related surgeries and hormone therapies would affect the readiness and deployability of transgender service members.
"I have a real concern with money being taken away from training and modernization and readiness to go to surgeries on soldiers that will render them non-deployable for a long amount of time," Hartzler explained to CNN.
"Recovery time, complications, and ongoing hormone treatments preclude many of them from being able to do a lot of the tasks needed in the military," she added.
Eric Fanning, who was the first openly gay Secretary of the Army after being appointed by President Obama in May 2016, said he takes a different approach on the idea of military readiness.
"When I think about readiness, I don't just think about today, I think about the future," Fanning told CNN Wednesday evening. "Opening up service to people who have been previously denied helps our readiness, certainly in the long term. It allows us to recruit from a bigger pool of people, and it ensures that our military reflects the society that it protects."
"And it lives up to the very values that our military is defending: freedom, opportunity, equality," Fanning added.
Rep. Duncan Hunter, a member of the House Armed Services Committee, was one of the 209 Republican lawmakers who supported Hartzler's proposal.
While Hunter drew criticism for saying that service members needed to "figure out whether you're man or a woman before you join," the California Republican stood by his comments.
"You should have a maturity level where you know what sex you are prior to joining because that's a big step, joining the US military," Hunter told CNN.
"Joining the military is a big deal, at least it was for me. When I joined, I knew I was going to go to war," he said.
The congressman entered active service in 2002 following the September 11 terrorist attacks, and served three combat tours overseas -- including two in Iraq and one in Afghanistan.
When asked about what effect proposals like the Hartzler amendment would have on transgender service members, Hunter suggested that it would impact in-unit cohesion.
"I would bring it down to the small unit level. Obviously, it's not going to matter if someone's a comptroller at the Pentagon and they're a transgender person," he said. "That's not going to have that much of an effect. But if you're in Afghanistan or Iraq, and you're living with 10 people on a little forward operating base, or intermixed with Iraqis or Syrians, I think it would have a major effect."
But Fanning disagrees with the California congressman on the issue of in-unit cohesion, telling CNN, "It appears to me that there's more concern for unit cohesion issues in Congress than there is in our military."
Navy Lt. Cdr. Blake Dremann -- who in September became the first known openly transgender service member to be promoted following Carter's repeal of the transgender military ban -- also pushed back on Hunter's comments.
"We are service members first, and our transition is part of that, but it's not the number one thing that we're concerned with. We are concerned with the mission and what's going on. We all make every effort to maintain our readiness," Dremann told CNN.
Throughout Dremann's career, the Navy lieutenant commander was deployed 11 times and has been stationed inside the Pentagon since 2015.
In an interview with Wolf Blitzer on CNN Wednesday, Hartzler expressed her concerns about the cost of medical treatments for transgender service members in the military.
"I've looked at this issue very, very closely, and this policy is going to cost $1.35 billion over the next 10 years alone just for sex reassignment surgeries for the transgender members of our service," Hartzler said.
When pressed further by Blitzer about how Hartzler calculated her cost estimates, the Republican lawmaker responded: "Well, our own office did that analysis and we feel very confident in it. There's one that's been done by the Family Research Council that says $3.7 billion. So the question is, though, should we be spending any tax dollars to do gender reassignment surgeries when we have soldiers who don't have body armor or bullets?"
"We need to be investing every dollar that we have to meet the threats that we're facing as a nation," she added.
But other researchers have pushed back against Hartzler's estimates. Jody Herman, Scholar of Public Policy and former Manager of Transgender Research at the UCLA Williams Institute, told CNN that the costs of transition-related surgeries cited by Hartzler are overblown.
The RAND study estimated the possibility of 30 to 140 new hormone treatments a year in the military, with 25 to 130 gender transition-related surgeries among active service members. The cost could range from $2.4 million to $8.4 million, an amount that would represent an "exceedingly small proportion" of total Defense Department health care expenditures, the study found.
"In the Family Research Council's analysis, they made a series of assumptions that, in my opinion, lead to a substantial overestimate of the cost," Herman said. "I think the cost estimates produced by the RAND Corporation a while back were based on more sound and defensible assumptions and are, therefore, more reliable estimates."
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Matt Thorn, executive director of OutServe-SLDN, an advocacy group for LGBTQ military personnel, slammed Hartzler's cost estimates, calling them "absolutely absurd."
"Even at their highest, they would never reach close to a billion dollars or close to her estimates in 10 years," Thorn said.
But Hartzler said she remains "very confident in our numbers," and added that "any way that you look at it, it is going to be a cost to the military."
The Trump administration's military ban announced Wednesday morning, as well as Hartzler's amendment, have generated significant criticism from LGBTQ advocacy groups.
Stephen Peters, press secretary for the Human Rights Campaign, told CNN that statements made by lawmakers like Hartzler and Hunter are "based in both ignorance and fear," adding that transgender service members "are willing to put their life on the line for our country, and they have earned the health care they and their families need and deserve."
The Human Rights Campaign (HRC) also released a statement responding directly to the military ban, calling Trump's decision "a dangerous and unpatriotic move to reinstate a ban on qualified transgender people serving in the military."
Combat veteran Sen. Tammy Duckworth, D-Illinois, also condemned the military ban in a statement: "When my Black Hawk helicopter was shot down in Iraq, I didn't care if the American troops risking their lives to help save me were gay, straight, transgender or anything else. All that mattered was they didn't leave me behind."
Fanning echoed Duckworth's sentiments, calling the ban "not just a setback for the transgender community, but a setback for the military, and a setback for our country, because this does not reflect the values upon which we were formed as a nation."
In light of Wednesday morning's military ban announcement, Mac McEachin, a former Army non-commissioned officer who entered the IRR reserves to attend graduate school overseas, expressed concern that the ban "would deal a huge blow to our military's readiness."
"If this were to go into effect, it would deal a huge blow to our military's readiness and would undermine both unit cohesion and the thousands of military leaders who support their troops being able to serve," McEachin, who is transgender, told CNN via email Wednesday.
"At the end of the day, transgender members want to serve like anybody else," McEachin added in a separate phone interview.