DISTRICT OF COLUMBIA: Treasury Secretary Jack Lew on Tuesday defended the Obama administration’s guidelines to banks conducting transactions with legal marijuana sellers as congressional Republicans questioned whether the guidance amounts to tacit federal approval of a drug illegal in most states.

Rep. Hal Rogers, R-Ky., chairman of the House Appropriations Committee, challenged Lew at a hearing, questioning whether guidance to banks on doing business with legal marijuana sellers represents a “rubber-stamp” by the federal government for a predominantly illegal activity.

“Without any guidance, there would be a proliferation of cash-only businesses, and that would make it impossible to see when there are actions going on that violate both federal and state law and that … would be a real concern,” Lew told the House subcommittee on financial services. “We thought that the clarity, bringing it into daylight, was a better solution.”