Let’s break this down:
If it’s true that revealing the particulars of this sort of technology could jeopardize national security (I don’t know if that’s the case, but let’s assume that it could), then the federal government can do one of two things. First, it can prohibit local police from using the technology, keeping it only for cases of legitimate national security. (We’ll also have to assume that using the technology for national security reasons is also constitutional.)
Alternately, the federal government could let local police use the technology, possibly violating the rights of American citizens in the course of investigations that have nothing to do with national security, then conspire with those same local police agencies to prevent American citizens from discovering that their rights may have been violated.
The Obama administration has chosen the latter.