President Trump is often loud and obstreperous, but not when it comes to choosing judicial nominees. On judges, there are no early morning tweet storms or rants. The president holds forth without restraint on practically every issue known to man. Judges are the lone exception. His sister, Maryanne Trump Barry, who recently retired at 82 as a judge on the 3rd U.S. Circuit Court of Appeals, has Trump’s ear. As his aides learned, he has great respect for her: After she suggested a 3rd Circuit colleague, Thomas Hardiman, for the Supreme Court, the president considered him twice for vacancies. Hardiman eventually lost out first to Neil Gorsuch and then to Brett Kavanaugh. But Hardiman is still a Trump favorite. Fifteen minutes after Trump announced Gorsuch was his first pick in January 2017, he phoned Hardiman. The president told him how much he liked him and hinted he’d consider him again. Hardiman would be close to a true “Trump-based nominee.” For a while, he drove a taxi. He grew up in the suburbs of Boston and went to the University of Notre Dame on a scholarship and then to law school at Georgetown. “He didn’t go to Oxford,” a Trump adviser noted. “He didn’t go to Harvard.” After working for five years in Washington, Hardiman, now 52, turned down an offer to work in New York for a national law firm. His wife persuaded him to...