Last week, The Times reported that the nation’s intelligence agencies have been collecting private e-mail messages and phone calls of Americans on a scale that went beyond the broad limits established in legislation last year. The article quoted the Justice Department as saying there had been problems in the surveillance program that had been resolved. But Justice did not say what those problems were or what the resolution was.

That is the heart of the matter: nobody really knows what any of the rules were. Mr. Bush never offered the slightest explanation of what he found lacking in the 1978 Foreign Intelligence Surveillance Act when he decided to ignore the law after 9/11 and ordered the warrantless wiretapping of Americans’ overseas calls and e-mail. He said he was president and could do what he wanted.

The Bush administration also never explained how it interpreted laws that were later passed to expand the government’s powers to eavesdrop. And the Obama administration argued in a recent court filing that everything associated with electronic eavesdropping, including what is allowed and what is not, is a state secret.

We do not think Mr. Obama will violate Americans’ rights as Mr. Bush did. But if Americans do not know the rules, they cannot judge whether this government or any one that follows is abiding by the rules.

In the case of detainee abuse, Mr. Obama assured C.I.A. operatives that they would not be prosecuted for actions that their superiors told them were legal. We have never been comfortable with the “only following orders” excuse, especially because Americans still do not know what was actually done or who was giving the orders.

After all, as far as Mr. Bush’s lawyers were concerned, it was not really torture unless it involved breaking bones, burning flesh or pulling teeth. That, Mr. Bybee kept noting, was what the Libyan secret police did to one prisoner. The standard for American behavior should be a lot higher than that of the Libyan secret police.

At least Mr. Obama is not following Mr. Bush’s example of showy trials for the small fry  like Lynndie England of Abu Ghraib notoriety. But he has an obligation to pursue what is clear evidence of a government policy sanctioning the torture and abuse of prisoners  in violation of international law and the Constitution.