WASHINGTON — She paused to maintain her composure as she spoke. She recalled the attacks, and how her reports of them were handled. The despair, she said, almost made her leave the military.

Senator Martha McSally, Republican of Arizona and the first woman in the Air Force to fly in combat, told a hushed Senate hearing room on Wednesday that she had been raped by a superior officer, one of multiple times she was sexually assaulted while she served her country.

“I thought I was strong, but felt powerless,” Ms. McSally said during a Senate Armed Services subcommittee hearing on sexual assault in the military. “The perpetrators abused their position of power in profound ways.”

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In sharing her experience — pride in her historic military service, betrayal over the assault and determination to help find a solution — the junior senator from Arizona offered one of the most powerful testimonies to date in the growing and heated debate on Capitol Hill over how to adjudicate claims of sexual assault in the military.