Congress shouldn’t reauthorize the government’s most potent snooping powers until it imposes stronger safeguards for Americans, a key conservative lawmaker said in response to a judge’s ruling that U.S. intelligence agencies tried to hide potential breaches of privacy rights. Rep. Raul R. Labrador, Idaho Republican, said Judge Rosemary M. Collyer’s April ruling is the latest in a string of warning signs that federal agencies need more oversight before Congress renews their broad powers under Section 702 of the Foreign Intelligence Surveillance Act. In particular, Mr. Labrador and several colleagues want to know how often Americans’ information is scooped up and...