introduced the USA Freedom Act.
According to the bill, the act's stated purpose is,
To reform the authorities of the Federal Government to require the production of certain business records, conduct electronic surveillance, use pen registers and trap and trace devices, and use other forms of information gathering for foreign intelligence, counterterrorism, and criminal purposes, and for other purposes.
The Act would amend a controversial policy outlined in Section 215 of the Patriot Act, which was authored by Sensenbrenner following the 9/11 attacks. 'Data mining,' also known as bulk data collection, authorized authorities to access "any tangible things," as long as they "specify" that the order is "for an authorized investigation . . . to protect against international terrorism or clandestine intelligence activities." In turn, massive amounts of personal data and information are subject to prying eyes without proof of probable cause.
http://www.youtube.com/watch?v=IEZAZFQWau0Additionally, the Foreign Intelligence Surveillance Court, or FISA Court, would be restructured to include a 'privacy advocate' who's charged with protecting citizens' constitutional rights through an appeals process.
On the Senate side, possibly the most outspoken proponent of current NSA policy has been Senator Dianne Feinstein (D-California). She's been the leading voice in the senate advocating for mass data collection, occasionally to her detriment. However, Leahy does have some allies, some of which from across the aisle.
Senator Rand Paul (R-Texas) has established himself as a privacy advocate, having introduced the Intelligence Oversight and Surveillance Reform Act with Oregon Democrat Ron Wyden last month.