(As affirming what is or is not constitutional without giving a legal reasoning on how that conclusion was reached.) At the last moment, they managed to add as signatories a few Puerto Rican Law professors none of whom is known for having expertise in Constitutional or International Law.
In an exercise of intellectual honesty a group of Puerto Rican professors, experts in Constitutional Law from Law Schools in Puerto Rico: the University of Puerto Rico School of Law, Inter-American University School of Law, and the Pontifical Catholic University School of Law, with an impressive body of writings and publications on Puerto Rico, it's status and position within American Empire, US Federal and Constitutional Law and International Law, have published a well-reasoned rebuttal to that patronizing letter. To read it, and the letter they sent to Congress, please click on the headline above.