The disappointing debut of Facebook’s IPO and Morgan Stanley’s seemingly  unequal treatment of its customers in providing inside last-minute cautions about the social network giant has investors and regulators upset, and lawyers readying for business. But when the nation's lawmakers start making the inevitable inquiries (key House and Senate committees already are making noises) about the deal and its chief underwriter, Morgan Stanley will not be defenseless. The financial services giant has plenty of political capital from campaign contributions and a veteran lobbying team.

Morgan Stanley has heavily invested in lobbyists. In the last three quarters of ...