 How can you tell? Because somebody signs a form and says, I want to register to vote. Right there on the form, it warns you, if you sign this form and any of it is untrue, and you're asserting that you have a right to vote, when in fact you're a foreign national and you know otherwise, then you're breaking the law. But the law is so very rarely ever prosecuted, so very rarely even detected, how would you know? Let's start with the census.