So it’s not just Sprint and the Justice Dept. that think the sale of T-Mobile USA to AT&T is a bad idea and should be stopped. Today, attorneys general for seven different states joined the DOJ’s suit to block the deal.

The seven states joining the suit — New York, Washington, California, Illinois, Massachusetts, Ohio and Pennsylvania — account for more than one-third the the U.S. population.

Illinois AG Lisa Madigan said she believes in the DOJ’s decision to block the merger because, “The proposed $39 billion transaction would substantially lessen competition for mobile wireless telecommunications services in Illinois and across the United States… Blocking this acquisition protects consumers and businesses against fewer choices, higher prices, less innovation, and lower quality service.”

“The addition of these seven states to the DOJ’s suit against AT&T only reinforces the seriousness of the consequences that a combined AT&T/T-Mobile would have on consumers,” says Parul P. Desai, policy counsel for Consumers Union. “These attorneys general have reviewed the proposed merger between AT&T and T-Mobile and come to the same conclusion we have – that it means higher prices and fewer choices. At a time when American families simply can’t afford to pay more for their wireless service, there is no room for a merger that would put 4 out of 5 national wireless contracts in the hands of two mega-companies.”

A recent price analysis survey of the voice and data plans available from AT&T and T-Mobile released by Consumers Union demonstrates that T-Mobile wireless plans typically cost $15 to $50 less per month than comparable plans from AT&T. In addition, the most recent cell-phone satisfaction survey by the Consumer Reports National Research Center shows that AT&T got lower marks than T-Mobile on almost every attribute rated, suggesting the proposed merger would be a setback to T-Mobile customers if it lead to service more resembling AT&T’s than T-Mobile’s.

A rep for AT&T released the following statement to Consumerist:

It is not unusual for state attorneys general to participate in DOJ merger review proceedings or court filings. At the same time, we appreciate that 11 state attorneys general and hundreds of other local, state and federal officials are publicly supportive of our merger. We will continue to seek an expedited hearing on the DOJ’s complaint. On a parallel path, we have been and remain interested in a solution that addresses the DOJ’s issues with the T-Mobile merger.

We remain confident that we’ll reach a successful conclusion and look forward to delivering the merger benefits of additional wireless network capacity to improve customer service, expanded LTE deployment to 55 million more Americans, $8 billion in additional investment, and a commitment to bring 5,000 wireless call center jobs back to the United States.

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