Mitt Romney’s main challenger, Rick Santorum, is facing criticism for saying Puerto Rico should adopt English as its primary language if it wants to become a U.S. state. Campaigning in Puerto Rico ahead of Sunday’s caucuses there, Santorum said Puerto Rico would need to make the change in order to comply with federal law. But the U.S. Constitution has no rule requiring the adoption of the English language as a requisite for new states. Santorum’s comments have cost him at least one delegate in Puerto Rico, who quit in protest.