Constitutional Conundrum

OK, so Mrs. Logan is in the limo with the Russian president and his wife, the very limo the route of which President Logan has revealed to terrorists bent on killing the Russian president. Presumably she may blow up in the next episode.

This raises a constitutional question: if the office of First Lady of the United States (FLOTUS) become vacant due to death or disability, does the Vice President's wife become the new FLOTUS?

Does the Mosaic law of levirate marriage apply constitutionally in this way? We need a Hebrew Bible scholar or a lawyer (at least one has read this blog) to weigh in on this question.