Trump complained there were too many Catholics on the Supreme Court: Michael Wolff book
Brett Kavanaugh shakes hands with President Donald Trump after being nominated to the Supreme Court. (AFP / SAUL LOEB)

President Donald Trump noticed that most U.S. Supreme Court justices were Catholic or Jewish -- and he didn't like it, according to a new book.

The president bristled when conservative groups pushed Brett Kavanaugh for the court, where six of the justices had grown up in the Catholic Church and the other three were Jewish, according to excerpts from Michael Wolff's new book reported by Axios.

Trump, who was brought up Presbyterian, asked if there weren't any WASP lawyers anymore, according to Wolff's forthcoming book, "Siege."

"You had all Protestants and then in a few years none," Trump said, according to Wolff. "Doesn't that seem strange? None at all."

Trump then complained that he couldn't publicly comment on that demographic shift on the court, Wolff said.

"But I can't say, 'I want to put a Protestant on the Court for better representation,'" Trump reportedly said. "No, you can't say that. But I should be able to."

That complaint was part of a broader theme that had first come up during the Neil Gorsuch nomination, which was waiting for him upon inauguration after Senate Majority Leader Mitch McConnell refused to hear Barack Obama's nominee ahead of the election.

Trump complained that he was limited to choices put forward by conservative legal groups like the Federal Society, rather than putting forward one of the many attorneys he personally knew.

"Why wasn't he being allowed to choose people he knew?" Wolff wrote. "He knew a lot of lawyers; why couldn't he just pick one?"