could you give me some case citations?
Under your scenario, anyone who happens to be physically in the US on election day could just walk in and vote ... I think your interpretation is way too liberal. I believe the protections clause has to do with due process, not entitlements, but do look forward to your citing those cases.
Don't like it? Too bad, it is a concept firmly entrenched in constitutional law by the courts for at least the last 60 -70 years. If you're asking me for legal research, the answer is for you to do your own at the nearest public library. Buy a used constitutional law case/text book or go on-line and ''AskJeeves'' or ''Google'' the phrase ''equal protection.''