And that's probably fine, because national security is more important than a singular crime.
If the federal government doesn't want certain sources and methods exposed in criminal court cases against non-spy citizens, then the federal government mustn't allow the use of those sources and methods against non-spy citizens in criminal court cases.
If the federal government doesn't want certain sources and methods exposed in criminal court cases against non-spy citizens, then the federal government mustn't allow the use of those sources and methods against non-spy citizens in criminal court cases.