The Veterans Affairs Department just says no to the Government Accountability Office's recommendations. The GAO says VA violated a 2006 law when it failed to set aside two contract solicitations for service-disabled, veteran-owned small businesses.

By law, agencies do not have to follow GAO's recommendations — but most do.

"The recommendation is followed in 99 percent of the time," said William Welch, chair of the Government Contracts Practice Group at General Counsel, in an interview with In Depth with Francis Rose.

"Congress can't tell the executive [agencies] what to do without passing a law signed by President," he said.

Despite the fact recommendations don't carry the weight of a mandate, generally agencies abide up "an written policy" that they should follow the recommendation, Welch said. If an agency does not follow a GAO rec, that agency must notify GAO and the Congress, he said.