Individually, the concrete steps President Obama announced Friday toward reforming the National Security Agency’s surveillance programs were modest. Taken together, though, they signal the end of an era of unfettered escalation in U.S. intelligence-gathering.

Since its establishment in 1952, the NSA’s history has been one of almost nonstop expansion. But for most of that time, the agency still faced limits on what kind of information it could gather and in the legal strictures that governed its programs.

That changed after the terrorist attacks of 2001, which prompted then-President George W. Bush to demand an all-out effort to collect every scrap of information available.

Bush brushed aside legal constraints and ordered the NSA to collect domestic telephone and email communications without court warrants. Later, Congress and the Foreign Intelligence Surveillance Court legalized much of that program retroactively, including the NSA’s collection of domestic telephone call records, known as metadata.

The president didn’t cancel any existing surveillance programs; indeed, he reaffirmed the government’s argument that telephone metadata should still be collected — though with new safeguards.

“The power of new technologies means that there are fewer and fewer technical constraints on what we can do,” Obama said. “That places a special obligation on us to ask tough questions about what we should do.”

The immediate practical effects of asking those questions will be few. The telephone metadata will still be there. But analysts who want to check U.S. telephone records will now need permission from the federal surveillance court.

A second Obama innovation — the idea that the NSA should treat foreigners the same way it treats Americans when it comes to privacy — is a revolutionary idea within the intelligence community, which is used to drawing a clear line between us and them.

The larger impact may come from a less obvious part of Obama’s reforms: his directives that intelligence agencies face more stringent oversight, and that the FISA court make public its decisions affecting privacy rights.

The president said that although the government should collect telephone metadata it shouldn’t be the one to hold it. That almost certainly means a vigorous debate in Congress as surveillance programs come up for reauthorization.

A year ago these issues were almost entirely unknown, even to members of Congress. But with Obama’s speech Friday, it seems certain the issues will have a full airing, and the president has made clear where he stands.

The era in which a president could order the NSA to expand surveillance programs with little oversight from Congress and no scrutiny from the public is over. That’s a big change, and a good one.

– Doyle McManus is a columnist for The Los Angeles Times.