The potential for corruption of the Foreign Intelligence Surveillance Act should warrant more, not less, oversight, Rand Paul writes.

Congress agreed to a less-than-constitutional standard as long as the targets were foreigners in foreign lands. Even many privacy advocates can accept this lower standard for foreign intelligence. But few, if any, privacy advocates believe that information vacuumed up without constitutional protections should be used against Americans accused of domestic wrongdoing.

Unfortunately, that's what we believe is happening now. In the vast dragnet of data files collected on foreigners under Section 702 of FISA, millions of bits of information are also collected on Americans. We don't know the exact amount because our overlords in the intelligence community won't tell us.

Apologists for any and all spying on anyone anywhere, foreign or domestic, want to permanently reauthorize this program. Permanent reauthorization would mean Congress would never again debate or oversee any abuses in this spy program. I can't think of an approach more callous in its disregard for our cherished Bill of Rights.

I will do whatever it takes, including filibuster, to prevent any reauthorization without new constitutional controls on this program.