From Slate: What Happens If Hundreds of Thousands of Puerto Ricans Flee for the Mainland United States?
The upshot: Puerto Ricans are US citizens and tend to vote Democrat. They probably aren’t fans of President Trump at the moment. This could upset the political balance in places like Florida. Will Republicans (cynically) offer a big aid package to keep them on the island? Will Democrats (cynically) block a large aid package to try and stack the deck in their favor in future elections?