"The Office of Senate Legal Counsel was established by Title VII of the Ethics in Government Act of 1978. The original legislation would have created an Office of Congressional Legal Counsel to serve both the House and Senate, but House conferees objected to a joint office, since they perceived the House and Senate to have somewhat different legal concerns. Although the idea of distinct legal counsel for Congress had been debated for several decades, events in the 1970s encouraged Members to take action. Extensive hearings held by the Senate Subcommittee on Separation of Powers of the Judiciary Committee, coupled with Congress's involvement in the Watergate investigations, indicated that there were potential conflicts of interest in using the Department of Justice as legal counsel to Congress. In addition, individual Member experiences with private legal counsel had sometimes proven unsatisfactory; observers agreed that there was a need for specialized experts dedicated to the legal issues involving Congress."
CRS Report for Congress, RS22891