A Walmart store in Florida quickly pulled it from its shelves, saying the shirt was "offensive" to some shoppers and apparently went against the chain's "family values."
This week, Hillary Clinton became the first woman nominated for president by a major political party. That means a woman, after 44 male presidents, finally stands a chance of winning the White House.
And a news clipping of Ruben's "controversial" shirt is doing the online rounds as an example of not just how far America has come, but also of how its notions were so antiquated just two short decades ago.
"We're in a new era now," a giddy Ruben told CNN on Wednesday. People, she said, aren't so threatened by the thought of having women in charge any more.
On the shelf, off the shelf
It still puzzles Ruben how anyone could have been offended by the shirt.
Ruben, a psychologist whose specialty was children's issues, had meant it as a way to boost little girls' self esteem.
It featured curly-haired Margaret from "Dennis the Menace" with arms stretched wide, chirpily making the declaration.
Ruben said the idea came to her from a "Dennis the Menace" strip where Dennis denies Margaret entry into his club, saying its for boys only.
"Open your eyes, Dennis, and join the rest of the world, " Margaret says. "Women make great cops, senators and representatives . . . Someday a woman will be PRESIDENT!"
Ruben had sold the shirts to women's groups before going to a local Walmart store in Miramar, Florida -- just north of Miami.
Two weeks after the shirt went on sale, the store pulled it after a customer complained.
"It was determined the T-shirt was offensive to some people and so the decision was made to pull it from the sales floor," a Walmart spokeswoman said at the time.
Her remarks were included in a story that ran in the Tuscaloosa News on September 3, 1995. And it's that clip that saw new life when Nick Kapur, a Rutgers University professor, tweeted it out Tuesday.
Life carries on
The store quickly put the shirt back on sale after outraged customers flooded it with calls, the Miami Herald reported
at the time. The Walmart chain ordered it for its stores nationwide.
It was eventually taken off again -- because Walmart said it didn't do well, the paper reported.
But the T-shirt lived on.
Ruben once met Clinton, back when Clinton was hawking her 1996 book, "It Takes A Village." Clinton was in West Palm Beach, Florida, for a book signing, and Ruben showed up -- wearing the T-shirt.
"She saw me walk in. She got out from the desk and came over to me and hugged me and kissed me and thanked me for doing the T-shirt," she said.
That wasn't Clinton's last encounter with the T-shirt. Ruben said she sent Clinton a shirt when her first granddaughter, Charlotte, was born in 2014.
Clinton sent back a note, thanking her for the "adorable" item.
And just because Walmart pulled the shirt decades ago doesn't mean demand for it died down.
A couple of years ago, Ruben sold an updated version of the shirt -- with the words "Someday is now" on the back -- to friends and at university bookstores in Pittsburgh, where she now lives.
Now that Clinton's a nominee, Ruben doesn't particularly care if demand for her shirt increases.
"I'm thrilled that we have a legitimate candidate, a wonderful woman" running for president, she said. "It's like a miracle."
The controversy still smarts though, Walmart told CNN on Wednesday.
"Wow, it still pains us that we made this mistake 20 years ago," the chain said in a statement. " We're proud of the fact that our country -- and our company -- has made so much progress in advancing women in the workplace, and in society."