Washington ? Citing FBI abuses and the attorney general’s troubles, senators peppered top Justice and intelligence officials Tuesday with skeptical questions about their proposal to revise the rules for spying on Americans.

Senate Intelligence Committee members said the Bush administration must provide more information about its earlier domestic spying before it can hope to gain additional powers for the future.

“Is the administration’s proposal necessary, or does it take a step further down a path that we will regret as a nation?” asked Sen. Jay Rockefeller, D-V.Wa., as he convened a rare public hearing of the Senate Intelligence Committee he chairs.

For two hours, National Intelligence Director Mike McConnell, National Security Agency Director Lt. Gen. Keith Alexander, Assistant Attorney General Kenneth Wainstein and their lawyers tried to parry increasingly dubious and hostile questions. They deferred many answers to a committee session closed to the public.

With little apparent success, they portrayed the administration bill as merely an adjustment to technological changes wrought by cell phones, e-mail and the Internet since the Foreign Intelligence Surveillance Act was enacted in the 1970s.

But Sen. Sheldon Whitehouse, D-R.I., said, “We look through the lens of the past to judge how much we can trust you.” Like other senators, he said that trust was undermined by recent disclosure that the FBI had abused so-called National Security Letters to obtain information about Americans.

The committee asked a year ago for Bush’s order – and the Justice legal opinions supporting it – that directed the National Security Agency after the Sept. 11, 2001, attacks to eavesdrop without warrants on Americans believed to be in contact with terrorists.

Democrats and civil liberties and conservative groups complained that the directive violated the Foreign Intelligence Surveillance Act, which requires warrants from a secret court for intelligence surveillance of Americans. Bush agreed last January to put the program under the court’s supervision.

Even though the administration insists the warrantless wiretapping was legal under the president’s constitutional powers, the administration bill contains a provision blocking lawsuits against telephone companies that cooperated. The administration has won most of the court battles so far over that spying, but one judge declared it illegal.