Antitrust attorney Joseph M. Alioto on Tuesday asked a federal judge in San Francisco to do what he says government regulators wouldn’t and halt the pending merger of United and Continental airlines.

The merger, recently green-lighted by the Justice Department and the U.S. Department of Transportation, could lead to higher fares and decreased services, Alioto, of San Francisco’s Alioto Law Firm, is arguing on behalf of 49 named plaintiffs.