The House is set to vote on holding Attorney General Eric Holder in contempt today for failing to meet Republican demands in a congressional probe into the controversial gun-sting operation known as “Fast and Furious.” The operation saw U.S. agents encouraging the sale of thousands of guns to middlemen for Mexican drug cartels in an attempt to gain access to senior-level figures within Mexico’s criminal organizations. At least four Democrats are expected to vote with Republicans in an apparent bid to retain the endorsement of the National Rifle Association, which backs the effort against Holder.