We have a remedy for federal constitutional violations, which is a Bivens action for damages: http://en.wikipedia.org/wiki/Bivens_v._Six_Unknown_Named_Age.... However, generally agents of the government are insulated from liability for Constitutional violations "insofar as their conduct does not violate clearly established statutory or constitutional rights of which a reasonable person would have known." See: http://en.wikipedia.org/wiki/Qualified_immunity.
With regard to NSA spying, there's nothing that's a clear violation of Constitutional law. The basic premise of the program, as we know it, collecting metadata and collecting calls between foreigners, is very likely Constitutionally sound based on existing precedent. If certain parts do turn out to be unconstitutional, it will be things like minimization procedures not being good enough at filtering out calls from U.S. citizens. And that's not a violation of "clearly established law." Coming down on the wrong side of an issue that judges and law professors can debate about at length isn't something that should give rise to Bivens liability.
With regard to NSA spying, there's nothing that's a clear violation of Constitutional law. The basic premise of the program, as we know it, collecting metadata and collecting calls between foreigners, is very likely Constitutionally sound based on existing precedent. If certain parts do turn out to be unconstitutional, it will be things like minimization procedures not being good enough at filtering out calls from U.S. citizens. And that's not a violation of "clearly established law." Coming down on the wrong side of an issue that judges and law professors can debate about at length isn't something that should give rise to Bivens liability.