The Church Committee forced the CIA and FBI to hide their programs with deeper and deeper compartmentalization—so their new lawyers could say “see ma, clean hands”.
They outsourced the nasty stuff:
—To private contractors
—To foreign allied intelligence agencies
—To other government agencies—easy to do with the large number of intelligence agencies (more than twenty)
In the early post Church Committee days the NSA took on a lot of the eavesdropping workload.