WASHINGTON — When the Senate was dragooned back to the Capitol in the final days of 2012 to vote on a last-minute deal to avert a sudden tax increase, most senators bristled at the inconvenience. Senator Ron Wyden, an earnest and wonky Democrat from Oregon, instead saw opportunity to again sound his cryptic but insistent warning about the alarming scope of government surveillance.

For hours before a C-SPAN camera and a mostly empty chamber, he expounded about his concerns over the nine-year renewal of a broad Bush-era surveillance law, loading his remarks with references to Ben Franklin, colonialists and obscure semiannual intelligence reports.

“I do not take a back seat to any member of this body in terms of protecting the sources and methods of those in the intelligence community,” Mr. Wyden said. But he warned that those efforts “should never be a secret from the American people.”

Late Wednesday, the secret was exposed, bringing to light the scale of government collection of communication information in the name of national security that Mr. Wyden and another serious-minded Western Democrat — Mark Udall of Colorado — have been hinting at for years.