Here is my reasoning: Melania Trump is Catholic. Many White House staffers and Secret Service personnel are in all likelihood Catholic. There would be security issues with some people in the White House trying to get away for Mass, most of all Melania. How much trouble would it be, for a priest to go to the White House every Sunday and celebrate Mass? I know there is no chapel in the White House (yes, I was surprised to learn this), but any serviceable room could be re-purposed into one.
And, of course, I am thinking that President Trump could attend as well. A factor in his possible conversion?