President Donald Trump, even before he was at the White House, had been basing part of his case for a wall at the United States-Mexico border on the fact that the Vatican is surrounded by walls. But there’s more to it than that.

Trump in a Cabinet meeting at the White House on Wednesday, while discussing the government shutdown, responded to criticism that his proposed border wall is immoral.

House Speaker Nancy Pelosi has on multiple occasions referred to the wall as “immoral” or an “immorality,” including this week.

“When they say the wall is immoral, well then you better … got to do something about the Vatican, because the Vatican has the biggest wall of them all,” he said. White House press secretary Sarah Sanders on Friday made a similar case in an appearance on Fox News on Friday.

“I wonder if she’s [Pelosi’s] going to go on a crusade and take down all the fences and walls across this country. I certainly hope not,” Sanders said. “I’m sure that the people that have them around their homes, the institutions that have them, whether it’s the Vatican or anywhere else, are not going to be real happy with the fact that Nancy Pelosi is calling their wall and their security immoral. It’s never been immoral to protect people.”

This is hardly the first time the Trump camp has pointed to the Vatican as a defense for the border wall. After Pope Francis criticized Trump during the 2016 campaign, saying that “a person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian,” many of his backers invoked the same argument.

Dan Scavino, who handles Trump’s social media, declared in a tweet that Vatican City is “100% surrounded by massive walls.”

Amazing comments from the Pope- considering Vatican City is 100% surrounded by massive walls. pic.twitter.com/g3iVLDVGe5 — Dan Scavino (@DanScavino) February 18, 2016

While there are walls around many parts of the Vatican, visitors can, for example, walk freely into St. Peter’s Square, the main plaza there.

The Vatican is a bad proxy for Trump’s border wall

Vatican City is an independent city-state that’s actually located in Rome. Measuring about 0.2 square miles, it’s the smallest country in the world. It is the center of the Catholic Church and ruled by the pope.

It’s true that much of the Vatican is surrounded by walls, some of which date back to the ninth century. But in this day and age, they’re not walls you can’t get around. You don’t need a passport to enter. Millions of tourists visit the Vatican each year.

“It isn’t all surrounded by walls, and it’s not like you need a separate visa or a passport to enter,” Gerard Mannion, a professor of Catholic Studies at Georgetown University, told the New York Times in 2016, when the Trump camp was first talking about the Vatican walls. “You wouldn’t know, almost, when you even entered Vatican City. There is a white line painted on the ground in St. Peter’s Square, but that kind of thing is not obvious everywhere.”

As the Times noted, there are “formidable walls” in Vatican City, and the entire place isn’t open for the public to roam freely — like where governance offices are, or where the pope lives. But there are plenty of places tourists can and do go, including St. Peter’s Basilica, St. Peter’s Square, and museums. Tickets are required for attending a mass at St. Peter’s Basilica for a general audience with the pope. They’re free.

“The fortifications were built a very long time ago,” James Martin, a Catholic priest and editor at large at America magazine, told CNN. “This pope didn’t build them — and he certainly didn’t bring them to keep out poor migrants.”

Trump visited Pope Francis at the Vatican in 2017 and must have noticed the walls — and that he got past them.

A wall at the Vatican isn’t the same as a wall at the US-Mexico border

To be sure, there isn’t exactly an apples-to-apples comparison between a wall or fence around one’s home, say, and between international borders. Lots of people have fences around their houses, or institutions have them delineating their properties, or, in this case, at the Vatican.

There are already barriers at much of the US-Mexico border, and what Trump wants from Congress now is some $5 billion more for about 200 miles of what he’s begun to refer to as steel slats. (The US-Mexico border spans approximately 2,000 miles, but even Trump has acknowledged that because of natural barriers, he doesn’t think a wall is necessary for the entire thing.)

Obviously, a wall around the Vatican, which, again, is about 0.2 square miles, is a much smaller endeavor than 200 miles of wall at a border — and less expensive, whoever pays for it. (Which, in the case of the border wall, will be US taxpayers, not Mexico.)

This isn’t the first time the White House has tried to invoke less-than-comparable barriers to defend its wall. He also tweeted that the Obamas have a wall around their property. As the Washington Post pointed out, he was wrong about that, too.