If breadth of backers was the main criteria, AT&T's $39bn purchase of T-Mobile USA would have sailed through regulatory review. After all, who could oppose a deal supported by interest groups as varied as the Louisiana Ballooning Foundation and the Association of New Jersey Orchestras?

But good corporate citizenry and lobbying expertise aren't the only criteria. And as the Justice Department's court challenge to the deal on Wednesday demonstrated, the deal was always long on hype for how it would help consumers, and short on robust legal arguments.