Fireworks in a Washington, D.C., courtroom don’t necessarily signal bad news for two telecommunications mergers under review by a federal judge, but they may portend a battle over merger law.

On Nov. 30, District Court Judge Emmet Sullivan heard the latest round of arguments in his review of the mergers between Verizon Communications Inc. and MCI Inc., and SBC Communications Inc. and AT&T Corp., which the Department of Justice approved in 2005.