T-Mobile and Sprint have agreed to merge. Now they’ll have to convince the government to let the deal move forward, which may not be easy. The companies have tried to work out a deal twice in the past and failed, partly over disagreements in terms, but also due to fears that the Obama administration would reject the merger. Their pitch to regulators this time? It’s all about 5G and the promise of fast mobile connectivity. Marketplace Tech host Molly Wood spoke with Mike Sievert, T-Mobile’s president and chief operating officer, about the details behind the deal.