Don't threaten me with a good time.

Though it is a mistake to assume Puerto Rico would certainly be solidly blue. The current political divide on the island is over statehood versus remaining as a territory, so there isn't an obvious Republican/Democratic sorting.

Most people just infer that from the Puerto Rican immigrants on the mainland who vote Democrat.

The island has fairly socially conservative politics on abortion and gay marriage. And a lot of the major politicians in Puerto Rico identify as Republicans.

When Hawaii and Alaska were admitted as states, people thought Hawaii would vote Republican and Alaska would vote Democratic.