Separation of powers
In the "United States v. Nicholson", the defendant moved to suppress all evidence gathered under a FISA order. 955 F. Supp. 588 (E.D. Va. 1997). The court affirmed the denial of the motion. There the court flatly rejected claims that FISA violated Due process clause of the Fifth Amendment, Equal protection, Separation of powers, nor the Right to counsel provided by the Sixth Amendment.