The United States came one step closer to making women eligible for the draft last month when U.S. District Judge Gray Miller of Texas ruled that an all-male Selective Service registration is unconstitutional. Miller’s ruling challenged a 1981 Supreme Court decision on the subject, which held that an all-male draft was “fully justified” because women did not serve in combat positions. With women eligible for all military service roles, including combat, Miller argued that their exclusion from registration for the draft was no longer supported by the facts.

The question of female draft registration has been under discussion for several years. In 2016, Congress created a commission to study the effectiveness of the Selective Service System and whether it should be expanded to include women. The commission released an interim report in January, which suggested that the final report, due in March 2020, would recommend undefined changes.

But this isn’t the first time the U.S. government has considered drafting women. As legislative debate about drafting women in 1945 shows, if the military need is great enough, women will be drafted no matter how uncomfortable lawmakers are with the prospect.

In his State of the Union address on Jan. 6, 1945, President Franklin D. Roosevelt called on Congress to amend the Selective Services Act to allow conscription of nurses, who were all women. His reasoning had nothing to do with equality under the law: The U.S. Army had a desperate shortage of nurses, a result of higher-than-anticipated casualty rates in the Normandy invasion the previous June and the subsequent bloody battles in the Ardennes during World War II. The War Department estimated it needed 20,000 additional nurses to provide quality care to wounded soldiers. There were plenty of nurses in the civilian population to draw on, but the need was too great to wait for recruiting efforts to provide the necessary numbers.

Congress was already accustomed to debating the use of women in the armed services as a result of serious wartime manpower shortages, with an emphasis on “man.” In May 1942, five months after the United States entered World War II, Congress passed an initial bill that established the Women’s Army Auxiliary Corps (WAAC), formed to serve “with” the Army, not “in” the Army, with enlistment limited to 25,000 women.

A year later, Congress converted the WAAC from auxiliary to active duty status with the creation of the Women’s Army Corps (WAC). The U.S. Navy, Coast Guard and Marines soon followed the Army’s lead. Several months later, Congress raised the ceiling on female enlistment, the first of several legislative changes required to fill the military’s needs. By war’s end, some 350,000 American women had enlisted in the various branches of the armed services.

Congress treated the proposed conscription of nurses as one more emergency expansion of women in the military. On Jan. 9, three days after Roosevelt’s speech, Rep. Andrew J. May (D-Ky.) introduced a bill that made nurses eligible for the draft, subject to the same exemptions as men. He opened hearings on the subject before the Committee on Military Affairs with the heartfelt statement that “it is hard to draft women” and a complaint that the War Department had waited until the matter was urgent to bring it to the attention of Congress.

The hearings focused on whether there was actually a shortage of nurses, who was to blame for it (with a certain amount of finger-pointing and backside-covering among the War Department, the American Red Cross, public health officers and various nursing organizations) and whether it was constitutional to draft members of a specific profession.

Beyond the repeated refrain that it was “hard to draft women,” no one discussed the underlying question of whether women should be drafted at all. When Rep. Clare Boothe Luce (R-Conn.) tried to amend the bill to make all women subject to conscription, the change was rejected — a clear indication that the proposed conscription of nurses was intended to serve a defined need rather than advance a matter of principle. Rep. R. Ewing Thomason (D-Tex.), who chaired several sessions of the hearings, summed up the situation when he stated that such a bill “would not survive 10 minutes on the floor but for the tragic present need.”

The House approved the bill, by a vote of 347 to 42, on March 28, 1945. Three weeks later, the Senate Military Affairs Committee sent a similar bill to the full Senate for debate. The Senate deferred action on the bill twice, on April 9 and May 21.

In the end, the bill died without Senate action, thanks to changed circumstances. Nurses across the United States rushed to enlist in response to Roosevelt’s description of the horrific need — and to the threat of conscription. (A number of women reportedly began the process with the clear intention that they would complete it only if conscription passed.) Germany’s surrender on May 6 ended the question altogether. With more than enough nurses in the pipeline to fill the estimated shortage and the expectation of a reduced number of new combat casualties, Undersecretary of War Robert P. Patterson asked the Senate to withdraw the bill on May 26.

With the immediate need over, drafting nurses was no longer necessary nor politically possible. Instead, with the end of the war in September, Congress was prepared to remove women from the military altogether, as it had after World War I. Attempts to pass a bill that would allow women to serve as permanent regular members of the armed services met with serious opposition in 1947, despite the support of Gen. Dwight D. Eisenhower and Adm. Chester W. Nimitz, both of whom were concerned with possible manpower shortages as the Cold War heated up.

During the 1945 hearings, Army Surgeon General Maj. Gen. Norman T. Kirk said flatly: “None of us wanted to draft nurses. It is the last thing we had intended until we saw it had to happen.” Over the course of the hearings, members of Congress and other representatives of the military echoed Kirk’s discomfort with the proposal to draft nurses and his conviction that it was necessary. Despite that conflict, the House ultimately voted overwhelmingly in favor of a bill to draft nurses.

A similar conviction of necessity has driven every expansion of women’s roles in the U.S. military, from the enlistment of female yeomen in World War I to the 2015 decision to allow women to serve in combat. It may well prove to be the deciding factor today. The Pentagon has already taken a position in favor of including women in registration for the draft for the most practical of reasons: a larger pool of potential conscripts in case of future need. While Judge Miller’s ruling is notable, necessity, rather than lofty principle or legal demands, will be what determines which roles women assume in the military in the years to come.