After Pope Francis suggested Thursday that Donald Trump "is not Christian" because he focuses so intently on a border wall and the mass deportation of millions of illegal immigrants, Trump supporters were quick to note that Francis's home, the Vatican, is fortified by — wait for it — border walls!

Which is not a bad retort. This is from Trump's social media director:

But as to the substance of the pope's comments, there's something else that many a Christian will notice. And that's the fact that he basically said something many of them support is "not Christian."

First off, here is the full quote from the pope:

"A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian. This is not in the gospel," the pope told journalists who asked his opinion on Trump's proposals to halt illegal immigration.

A November Washington Post-ABC News poll asked whether people wanted to deport "all" of the estimated 11 million undocumented immigrants in this country. And Christians were very evenly split, with 46 percent in favor and 52 percent opposed. (Catholics were slightly less in favor, with 37 percent supporting that particular policy.)

A January Post-ABC poll, meanwhile, showed 42 percent of Christians said immigrants from other countries weaken the United States. The pope didn't weigh in on this particular idea, but his philosophy is generally much more pro-immigrant than that.

Finally, while we don't have good data on how many Christians favor a border wall, Americans overall are pretty split, with 45 percent in favor and 49 percent against, according to a January CBS News/New York Times poll. And given the fact that Christians tilt more conservative than the population overall on almost every issue, it's a good bet that half or more of Christians support a border wall.

Now, it's important to note here that the pope didn't just cite these policies — he cited "a person who thinks only about" border walls and not "building bridges." So you could make the case that his criticism applies more to Trump than to other Christians, given Trump's almost-singular focus on a border wall and deportation, along with his divisive rhetoric.

But it's also true that, for many conservative Christians in this country, the immigration debate starts and ends with a border wall and deportation. That's basically the operating principle of today's heavily Christian Republican Party, in fact.

In other words, Donald Trump is hardly the only person in America who is probably taking exception to Pope Francis's comments today.