Perhaps when entering the country, and there is a risk of deportation, and the difficulty of immigrating legally puts far too many people on unsafe footing due to the constant risk of being reported, but on a basic, everyday level you have the same rights. If you get pulled over on the road, the cop can't search your car without a warrant, whether you're a US citizen or just a tourist.
This is true, but I would argue that it's only true because of the assumption that random driver being pulled over is a citizen (or rather that you can't ask a citizen if he or she is a citizen. This was part of the big deal with Arizona's new laws a year or two ago).
When writing my post, I was considering the "unlimited detainment", and lack of due process for non-citizens in too many special cases.
