As a Catholic whose views are in line with those of Pope Benedict XVI, US Supreme Court Justice Antonin Scalia personally opposes abortion.

But what explains his opinions in every abortion-related case that has come to the court since Scalia became a justice in 1986 is not his Catholicism but his “originalist” interpretation of the US Constitution, the author of a new biography of Scalia said Monday.

Speaking at an “On the Issues” forum at Marquette Law School, Joan Biskupic told host Mike Gousha that Scalia has “parallel passions,” Catholicism and the law.

”You just cannot forget that he’s so darned conservative on the Constitution, independent of his Catholicism,“ Biskupic said. Scalia simply does not see anything in the text of the Constitution that supports giving a woman a right to have an abortion.

Biskupic said she found in researching Scalia’s life that his views on the Constitution have been consistent for all his adult life. People she talked to from each stage of his life described him as an originalist.

Biskupic described Scalia as a “many-layered” person.

She said he is charming, gracious, tough, bullying, arrogant, a lot of fun, and prickly, at different times. She quoted Justice Ruth Bader Ginsburg saying, “Sometimes I’d like to strangle Nino, but I love him.” Ginsburg and Scalia are philosophical opposites on many legal matters, but are close personal friends. On the other hand, Biskupic said, as much as Scalia and Justice Clarence Thomas are close on the court, they are not close socially because, in the words of Thomas, Thomas likes to go home and watch college football while Scalia likes to go home and listen to opera.

Biskupic interviewed Scalia on the record a dozen times for her book, even after he initially said he wouldn’t agree to talk to her. He changed his mind after she saw him at a social event and began describing what she had found during visits to Trenton, N.J., where Scalia was born.

Biskupic, who covers the Supreme Court for USA Today, said that, at 73, Scalia is at the apex of his career because his influence has grown and he can attract support from other justices, including Chief Justice John Roberts and Justice Samuel Alito Jr., to put together majorities in some cases. In some prior periods, when his views were in a clear minority, Scalia found being on the court so frustrating that he considered resigning, she said.

Scalia is “an amazing stylist” when it comes to his written opinions, she said, which is one reason his opinions are so widely read. “He’s so clever, so engaging in his writing,” she said.

Biskupic noted a little-known Milwaukee touch to Scalia’s life – he spent a summer as a clerk at Foley and Lardner between his second and third years of Harvard Law School. But he did not want to come back to Milwaukee to practice after he graduated.

Biskupic’s book, “American Original: The Life and Constitution of Supreme Court Justice Antonin Scalia,” was published by Sarah Crichton Books. Biskupic received a bachelor’s degree from Marquette and covered the Supreme Court for the Washington Post before joining USA Today. She previously authored a biography of Justice Sandra Day O’Connor.