Carl Bernstein, one of the pair of Washington Post reporters known for reporting on the Watergate scandal, has sided with Pope Francis over Donald Trump in their recent dust up that began when Francis suggested Trump is not a Christian because of his views on immigration.

"Pope Francis is a great leader in the world today and what the pope said was really quite apt about Donald Trump," Bernstein told a TMZ reporter on Friday. Bernstein, who is Jewish, said he agreed with the notion that closing borders is not a "a very Christian attitude or a very humane attitude."

Earlier in the week, Pope Francis was asked by a reporter aboard a papal airliner while returning back to Rome from a six-day visit to Mexico whether a "good Catholic" could vote for Trump for president.

Anyone who "thinks only about building walls, wherever they may be, and not building bridges, is not Christian," answered Francis, without directly mentioning Trump's name.

Responding to Francis' comments, Trump called the pope "disgraceful."

A Vatican spokesman later walked back Francis' comment, explaining that the pope was "in no way" specifically condemning Trump.

Bernstein, who is co-author of a biography about Pope John Paul II, titled His Holiness, was also asked what he thought about Trump's suggestion that the wall he wants to build along the Mexican border would be like the "massive" walls around the Vatican.

"Of course the Vatican has walls. It was built in the 15th century. The Vatican has had its days as a terrible institution too," Bernstein said.

That does not mean that Pope Francis wants to wall off the church from "modernity" and the "gospels of Christ," Bernstein said.