The House of Representatives cited Attorney General Eric Holder in contempt of Congress for not turning over the documents about the gun-running scheme that went awry.
Lew said in an interview on CNN's "State of the Union" that every document related to Holder's decisions on Fast and Furious was handed over to the congressional committee investigating the incident.
"This is not about the facts. The facts are out there. This is about a committee that is on a path towards turning a review of policy into a political witch hunt," Lew said. "They're looking for documents that have nothing to do with what they're asking questions about.
"There has to be the ability for a president to get confidential advice. There has to be an ability for Congress to use its speech and debate clause. ...
"There was an unprecedented amount of cooperation and providing insight into all the decisions made up to the point of the correction that Congress was given about the policy itself and about the testimony. What they are looking for now are internal kinds of documents that they know are not appropriate," he said.