T-Mobile US Inc. and Sprint Corp. could be just weeks from finally announcing a merger. It would be the largest deal of the year, but even if a deal is announced, there’s no certainty it will happen. Regulatory approval is far from assured. Veteran telecommunications analyst Craig Moffett explains why the companies want to merge now and how the government may interpret a merger. He also gives a gloomy outlook for the entire U.S. wireless industry to host Alex Sherman.