Bill would provide for special advocate for Americans' privacy to argue before the court when the US makes surveillance requests

Three US senators announced bills on Thursday that proposed the most sweeping structural changes to the secret court that oversees the legal basis for surveillance activities since it was set up 35 years ago.

Senators Richard Blumenthal of Connecticut, Ron Wyden of Oregon and Tom Udall of New Mexico, all Democrats, want a special advocate for Americans' privacy to argue before the so-called Fisa court when the government seeks extraordinary surveillance requests. They also propose to diversify the powerful secret court ideologically and geographically.

"The constitution needs zealous advocacy," Blumenthal said Thursday, in advance of the twin bills' introduction, a day before Congress recesses for August. "The client will be the constitution."

A separate measure from the three senators would still allow the chief justice of the US supreme court to select the Fisa court judges, but would require him to pick them from nominations brought by the chief judges of the US federal circuit courts. The court's membership would expand to 13 judges, essentially representing each of the federal courts nationwide, from the current 11.

The move is a substantial overhaul of a court that most Americans did not know existed eight weeks ago, when the Guardian published an April order from one of its former members, Roger Vinson, ordering Verizon to provide the National Security Agency with the phone records of all its customers.

Currently, the Fisa court has only one petitioner: the government. In its 35-year history, it has rejected 11 out of more than 34,000 surveillance requests, prompting its current presiding judge, Reggie Walton, to aggressively fight the perception it is a rubber stamp.

During a Senate judiciary committee hearing on Wednesday, senators of both parties professed incredulity that the Fisa court would define a section of the Patriot Act allowing the government to collect "tangible things" that are "relevant" to an ongoing terrorism or espionage investigation in a manner that allowed the government to collect the phone records of every American, without suspicion of wrongdoing and connection to any specific investigation.

Wyden, who has called such secret redefinitions "secret law", described the creation of a constitution advocate before the Fisa court as the next logical step in reforming surveillance.

"This is a critical piece of the reform puzzle that we're going to pursue in the days ahead," Wyden said.

Wyden is one of a number of legislators who was due to meet President Obama on Thursday to discuss surveillance matters, as congressional displeasure with the phone records bulk collection persists. The House of Representatives came within seven votes of authorizing the end of the program last week.

Before the meeting at the White House, the four leaders of the Senate and House intelligence committees, all of whom strongly support the bulk phone records collection, issued a statement saying the NSA had conducted the program "in a lawful, careful manner".

"We understand the American people have concerns as the result of the program's disclosure, and the inaccurate and reckless way it has been characterized," said the statement by senators Dianne Feinstein and Saxby Chambliss, and represenatives Mike Rogers and Dutch Ruppersberger.

"These authorities are used in a manner consistent with the law and the constitution, and we are working with our colleagues in the House and Senate to reassure the American people and look for ways to improve transparency and strengthen privacy protections without undermining the program's effectiveness."

While it is unclear how often the proposed constitutional advocate would interject objections to government requests for surveillance, Udall said the sheer prospect of an adversarial process would be a powerful institutional transformation.

"If you have an advocate in there whose focus is the constitution and civil liberties, it unleashes the court to be able to do the job that typically courts do, which is weighing and balancing," Udall said.

"When you only hear from one side, that's where you run into a problem."