The bill of rights specifically delineates protections that apply to "people" and protections that apply to "citizens." The dialogue is often about civil rights violations of American citizens, but the original language is more often "people."

From Yick Wo v. Hopkins

The rights of the petitioners, as affected by the proceedings of which they complain, are not less because they are aliens and subjects of the emperor of China. . . . The fourteenth amendment to the constitution is not confined to the protection of citizens. It says: “Nor shall any state deprive any person of life, liberty, or property without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.” These provisions are universal in their application, to all persons within the territorial jurisdiction, without regard to any differences of race, of color, or of nationality; and the equal protection of the laws is a pledge of the protection of equal laws. . . . The questions we have to consider and decide in these cases, therefore, are to be treated as involving the rights of every citizen of the United States equally with those of the strangers and aliens who now invoke the jurisdiction of the court.

Example from the other side: http://www.foxnews.com/opinion/2010/01/07/kt-mcfarland-chris... With the Detroit bomber we now have a clear pattern that reveals how the Obama administration deals with terrorists – try them in civilian courts with the full rights of American citizens... The president is treating terrorists like citizens and citizens like terrorists.

Note: I've taken both these examples from an excellent Glenn Greenwald article on the subject