Congress has scheduled another hearing, for April 17, on the proposed merger between Sirius Satellite Radio and XM Satellite Radio. Like all significant mergers, this one deserves scrutiny by the antitrust and regulatory authorities. Congress legitimately has an oversight role as well. But keep a keen eye: the way in which this merger is handled will tell much about whether our government officials grasp how dramatically communications and information services markets are changing. I am concerned that the Department of Justice antitrust officials and the Federal Communications Commission regulators charged with reviewing the merger do not adopt an unduly narrow...