Cassidy said she watched the "witch hunt" unfold as the Office of Naval Investigation began its crusade to cleanse the civilian service of homosexuals.
She said many of her friends were called in: "They sat behind the big lights and started grilling them, saying, 'We know you're a homosexual, because your partner is in the next room.' She told us, 'You might as well confess.'"
Her moment of clarity came while looking out her window when she saw 15 to 20 Navy women -- "in those terrible gray, seersucker suits" -- and realized they had been rounded up for firing.
"They had been identified as homosexuals," she said. "They had their heads held high and their shoulders squared and it made me shiver."
Their parents would receive the dreaded letter: "We are sending your homosexual child home," she said.
Up until that point, Cassidy never frequented lesbian bars, because it was too dangerous. Gossip could destroy a career.
She had learned that she had been identified by an enlisted woman. "I had never said a word to them," she said. "I don't know what it is that I did -- or how I walked or held myself. But word spread quickly."
Lesbians were careful to only socialize at private parties, and often with gay men for protection from scandal, women on one side and men at the other. She remembers a time when they heard a knock at the door, and women scrambled to change their seats.
"It was automatic," Cassidy said. "We'd be guy, girl, guy, girl, with our hands on the guys and their arms all around us."
Progress has been made but, director Howard said, "There are still battles to be fought."
President Obama is considering an executive order to create anti-discrimination policies for private government contractors.
"That would be huge, particularly in these times of outsourcing," he said, citing a UCLA Williams Institute study estimating that a half-million gay people work in private companies who do business with the government. Thirty states still have no anti-discrimination laws.
Howard said that learning this history is important, because the mass firings set the stage for the homophobia that still persists today in schools and in the workplace.
As for Cassidy, she would have stayed on in active duty. "I loved the Navy," she said.
"There are so many people who have no idea what that time was like," she said. "They have no idea of the kind of fear ... They made us feel as though we were below consideration."
But Cassidy and Howard acknowledge significant progress in LGBT rights since the McCarthy Era firings. Gay marriage is legal in seven states and the District of Columbia.
Cassidy is now living proof of new societal attitudes. She and her same-sex partner of 13 years were legally married in Washington, D.C.
The tragedy of what happened 59 years ago was, Cassidy said, "that every one of us had joined the Navy because we were so proud of our country and wanted to serve."