If this were not the case, the drafters of the Bill of Rights would have not used the word 'person' if they intended that section to apply only to 'citizens'. Legislatures are presumed to mean what they say and the fact that both 'citizen' and 'person' are used in the Bill of Rights must be interpreted to mean that the Congress intentionally used two different words to convey different levels of protection for the rights of 'citizens' than for 'persons in general'.
Frenchman Z. Moussoui's computer could have been searched, and we quite possibly could have gained information about the terrorist attack in time to prevent it, if people in this country were not so concerned with our enemy's fictitious "4th Amendment rights". The Constitution does not necessarily protect persons who are not "OF THE UNITED STATES". It says in the preamble who it was established for.
We're going to commit suicide, if we extend BoR protections to all "persons" who are not PEOPLE OF THE UNITED STATES, blindly. After we're vaporized in a mushroom cloud, who's going to uphold the Bill of Rights? Or maybe you're counting on the mushroom cloud not to get you? Survival is priority one. Grant unto the foreign, visiting, terrorists with their illegal visas, the same rights they granted to the citizens in the WTC.