Joan Biskupic says her fourth book about a member of the United States Supreme Court involved “my most difficult subject” – Chief Justice John Roberts. But, perhaps in good part for that reason, it is also attracting much attention.

Roberts is “a very reserved individual,” Biskupic said during an “On the Issues with Mike Gousha” program in the Lubar Center at Marquette Law School on Tuesday. “There’s a lot that you see, but much more that’s held back.” She had the benefit of eight interviews, covering more than twenty hours, with Roberts, but she said she wonders still about what is not known about him.

However, Biskupic’s newly-published biography, The Chief: The Life and Turbulent Times of Chief Justice John Roberts, does offer a lot, some of it not reported previously, about Roberts, who has been chief justice since 2005.

And in addition to a richly detailed description of Roberts’ life, the book breaks new ground in describing how Roberts came to be the decisive vote in upholding the constitutionality of the Affordable Care Act, often known as Obamacare, in 2012. Biskupic describes how he initially took positions opposing the constitutionality of the law during the court’s work on the case, then switched his views.

“I think he definitely did not want the whole law to go down,” she said. “I’m fine with saying I don’t know why, for sure.”

Biskupic,, who received her undergraduate degree from Marquette University, described Roberts’ life, from his early years growing up in “an oasis community” near Gary, Indiana, through his rapid career path ascent as a law clerk for then-Justice William Rehnquist, then as a Justice Department official during the Reagan administration, then as a successful attorney in private practice (he argued 39 cases before the Supreme Court) and, starting in 2003, as a federal appeals court judges. He was 50 when he was named chief justice two years later.

Although Roberts has talked in some widely-reported graduation speeches about the value of overcoming adversity, “he has been blessed” with little in the way of setbacks or failures, Biskupic said. ”He’s had almost perfect timing throughout life.”

While some suggest Roberts has moderated his views in order to protect the Supreme Court’s standing, Biskupic said there are subjects where he has been steady in his conservative views. She pointed to cases involving issues of racial discrimination (he is firm in his view that solutions that involve racial factors are wrong) and voting rights.

But she said, “there is definitely no love lost” between Roberts and President Donald Trump. The more Trump talks like the Supreme Court is in his pocket, the more Roberts will want to be sure that is not so, Biskupic said.

Roberts works to present the court as a place of collegiality, Biskupic said. “It’s definitely not that way, at least not all the time,” she said. There are justices on both the left and right who have questioned whether Roberts has been a straight shooter with them.

Biskupic’s previous books have focused on Justices Sandra Day O’Connor, Sonia Sotomayor, and Antonin Scalia. Biskupic worked previously as a reporter covering the Supreme Court for the Washington Post and USA Today ad is now a legal analyst for CNN.

To view video of the hour-long program “On the Issues” program, click here.