In this case, the government will be asking a federal judge in California to dismiss a lawsuit filed by the Electronic Frontier Foundation against AT&T for its alleged complicity in warrantless government surveillance of its customer's internet and telephone communications. The EFF alleges that AT&T gave the government access to a massive phone billing database and helped the NSA spy on its customers' internet use.
The state was breaking the law. As such, they have no secrets to protect, other than the fact that it broke the law. Now, I'm no conspiricy nut, but nothing says "cover-up" any better than that.