A top Republican on the House Judiciary Committee warned spy officials at a hearing Wednesday that their surveillance authorities under USA Patriot Act Section 215 will expire if the government does not rein in its surveillance practices.

The warning was a rebuke to intelligence officials who have defended the mass metadata collection program for more than a month as legal under the 2001 Patriot Act. Specifically, the government has justified the National Security Agency’s surveillance metadata program, revealed by leaker Edward Snowden, under USA Patriot Act Section 215, known as the “business records” provision. But the program has raised alarm bells among some lawmakers who say they never intended for Section 215 to be used in that way. Section 215 authority is set to expire in 2015 without reauthorization from Congress, and now, for the first time, a member of Congress, and a leading conservative, said those powers may be in jeopardy.

Rep. James Sensenbrenner, R-Wis., one of the original authors of the USA Patriot Act, told officials during a House Judiciary hearing that Congress will allow their Section 215 authorities to expire entirely in 2015 unless the government accepts changes to the program.

"There are not the votes in the House of Representatives to reauthorize Section 215," Sensenbrenner told a panel of witnesses from intelligence agencies testifying on the government's use of its authority under the Foreign Intelligence Surveillance Act.

Unless the government changes how it is applying Section 215, he said, “you’re not going to have it anymore.”

Sensenbrenner specifically went after how the government -- and the Foreign Intelligence Surveillance Court, which authorizes the surveillance programs -- is interpreting the “relevance” standard in Section 215. The relevance standard is meant to limit surveillance to subjects deemed relevant to the investigation. Sensenbrenner said he was dismayed to see that standard being used to expand the government’s surveillance powers rather than to limit them. “Doesn’t that make a mockery of the legal standard?” he asked.

Sensenbrenner wasn't alone in his prediction. "I share with Mr. Sensenbrenner the belief that this will not be able to be sustained," Rep. Zoe Lofgren, D-Calif., said during the hearing. The metadata program has "gone off the tracks legally."