This Argument Seems Strong To Me

     From the Supreme Court amicus brief of the American Bar Association in U.S. v. Vaello-Madero, the case presenting the question of whether it is constitutional to deny SSI benefits to American citizens who reside in Puerto Rico:  

... As a threshold issue, all of the government’s justifications for the SSI law start from the premise that it has legitimate interests in treating Puerto Rico differently because of its territorial status. ...     

However, “[i]t is well settled that the Equal Protection Clause ‘protects persons, not groups.’” Engquist v. Or. Dep’t of Agric., 553 U.S. 591, 597 (2008) (citing Adarand Constructors, Inc. v. Peña, 515 U.S. 200, 227  (1995)). The “persons” whose equal-protection rights are implicated in this case are the particular Puerto Rico residents such as Mr. Vaello-Madero who would otherwise qualify for SSI, which is only a subset of Puerto Rico residents as a “group” or “jurisdiction.” The government’s justifications for the law must supply a rational basis for treating these particular individuals differently than similarly situated individuals who do qualify for SSI because they reside elsewhere. But because the government only focuses on how all Puerto Rico residents can be treated as a group, it fundamentally fails to provide a rational basis for discriminating against Mr. Vaello-Madero and similarly situated individuals who happen to reside in Puerto Rico. ...