Scalia's love of debate was one of the things that drew him to Ginsburg- a woman with whom he disagreed on many things, including many aspects of the law. But Scalia admired Ginsburg's determination, especially in an era when it was harder for women to achieve the career success that Ginsburg attained.
"She was a sparring partner with him…My father liked people who would match him, and who would push back," Father Paul noted.
"He would hire clerks who would challenge him on things. He wanted that. He wanted that intellectual engagement, because he knew that it was good for him. It would test his line of thought and his principles."
As the longest serving justice on the bench at the time of his death, Justice Scalia is remembered for his strong emphasis on interpreting the law as it was originally written and intended. Ginsburg, in contrast, believed in a "living Constitution" that could be adapted to the times. The two frequently criticized each other's legal reasoning and opinions.
In their nearly 23 years together on the bench, they heard and debated hugely consequential cases having to do with such issues as abortion, same-sex marriage, and the 2000 presidential election.
When asked about their friendship in a 2014 interview, Justice Scalia seemed to brush off suggestions that it was somehow extraordinary.
"I have never gotten angry at Ruth or at any of my colleagues because of the way they voted in an opinion. I mean, if you cannot disagree with your colleagues on the law without taking it personally, you ought to get another day job," Scalia said.
"It's just not the kind of a job that will allow you to behave that way. Ruth and I disagree on the law all the time. It's never had anything to do with our friendship."
Another facet of the Scalia-Ginsburg friendship was a mutual sense of humor, Scalia's sons said. Scalia possessed a rich sense of humor, and loved to sing and tell jokes.
"I think one of the reasons Justice Ginsburg liked my father is that he cracked her up...She said that very few people could make her laugh out loud; basically it was her husband, and my father," Chris said.
Scalia and Ginsburg first struck up a friendship in the 1980s, when they served together on the D.C. Circuit Court of Appeals. Chris said Scalia used to whisper jokes to Ginsburg during arguments, and she would have to pinch herself to keep from laughing out loud.
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When they again sat together on the bench, this time on the Supreme Court, Scalia would pass notes to Ginsburg with jokes or funny comments on them.
"I think it strikes us as weird in part because we live in such polarized times, and because they are themselves kind of heroes of very different sides- [Ginsburg] is a legend for the left, and my father is kind of the equivalent for the conservative legal movement. So I think that makes it even stranger to people," Chris said.
"Obviously they had big differences as far as their jurisprudence went. But it's really not that strange when you consider the many things they had in common."
These similarities included growing up in New York around the same time, enjoying good food and wine, and a love of opera.
There even exists a comedic opera about the two justices, called Scalia/Ginsburg, written by a graduate of the Yale School of Music-turned-law school student. The opera includes many jokes and gags that riff on the two's intellectual and philosophical differences, but also includes moments of unity between the two characters, including a heartwarming duet.
Obviously, there were elements of their worldviews- very significant elements- that Ginsburg and Scalia did not share. Scalia was a devout Catholic, and Ginsburg and her husband Marty were secular Jews.