WATCH: Allyson Robinson Slams Pentagon's Lack of Leadership on Trans Military Ban

Advocates who want to see the U.S. become the 19th nation to allow transgender citizens to serve openly in the armed forces are ramping up pressure on the Pentagon to revise an outdated policy that currently prohibits trans Americans from serving in the U.S. military.

Former Army captain and West Point graduate Allyson Robinson -- one of the most visible advocates pushing for open service -- offered some of her sharpest remarks to date on the issue when she appeared on MSNBC's Ronan Farrow Daily Thursday.

Current military policy declares a transgender identity or any gender-affirming treatment to be indicative of a "psychosexual condition" and grounds for discharge, thanks to a medical regulation that has not been updated since the 1970s. Because the ban is simply a medical regulation, it does not require congressional action to revise -- which is why advocates like Robinson are looking to outgoing Secretary of Defense Chuck Hagel to initiate a review that would see the ban dropped.

On Thursday's segment, Robinson explained that although "our understanding of transgender people, transgender identities, has advanced significantly" since the relevant regulations were written, "the Pentagon is now way out of step with the American Psychiatric Association, the American Medical Association, and ... with 18 of our allies who figured this out a long time ago."

Robinson herself is a transgender woman and the director of policy at SPARTA, an association of LGBT people currently serving in the military as well as veterans and LGBT advocates and allies committed to repealing the transgender military ban and establishing true equality in the U.S. armed forces.

Several prominent studies have determined that there is "no compelling medical reason" to continue to deny open military service to transgender Americans, as a study backed by a former U.S. Surgeon General and performed by the Palm Center concluded last year. A nine-member commission, including several retired generals and flag officers, concluded a three-month study last August with the recommendation that changing the current regulations to allow trans citizens to serve openly would be "neither excessively complex or burdensome."

Last May, Hagel said he believed the regulation banning open service by trans Americans should be "continually reviewed," and that he was "open" to conducting that review. But nearly a year later, the Pentagon has not initiated any formal review, as The Advocate reported late last year.

"What we lack at this point, it seems, is leadership," said Robinson. "We lack will of leaders in the Pentagon to take the appropriate steps to protect these service members and allow them just to serve their country. That's what they want to do."

Despite her critique, Robinson is optimistic that the Pentagon will in fact review the policy in the coming year. Last month, she authored an open letter to Hagel's probable successor, Secretary of Defense nominee Ashton Carter, in The Advocate echoing many of the points she made on Farrow's program.

"Secretary Hagel came into office talking about 'taking care of the troops,' and that anyone who was qualified to do so should be allowed to serve their country," Robinson told Farrow. "I know that Dr. Carter shares those same values. What I hope we'll see happen, though, is that, if for no other reason than simple collegiality, that Secretary Hagel will announce and initiate a review of these policies prior to leaving office, and get it off the table for his successor."

"Mr. Carter's got far more important things -- ISIS, for example -- to be concerned about," Robinson concluded. "Let's just get this done."

Watch the full interview below.