House Republicans last week took aim at the U.S. Justice Department’s alleged mishandling of a federal gun smuggling operation that critics contend allowed thousands of firearms to flow unfettered to Mexico and into the hands of drug cartel members.

For several months leading up to the House Oversight and Government Reform Committee hearing, GOP leaders pounded Attorney General Eric Holder Jr. with questions and written demands seeking information about top-level authorization and supervision of “Operation Fast and Furious.”