The merger of Sprint and T-Mobile US will reshape the competitive landscape in the U.S. mobile market. Last week, the merger cleared what was widely seen as the last major hurdle to a successful closing: U.S. District Court Judge Victor Marrero rejected the claims of a group of state attorneys-general that the merger of T-Mobile US and Sprint would reduce competition.

With that ruling, T-Mobile US could be looking at closing the merger as soon as April 1, although there still some moving parts: a separate legal approval for the related Dish Network settlement (which includes asset divestment to Dish of Sprint’s prepaid businesses, some 800 MHz spectrum and access to wireless infrastructure sites so that it can become a fourth facilities-based competitor) and approval from the California Public Utility Commission.

The 170-page ruling by Marrero covers past, present and future: he goes through some of the telecom history that brought both parties to the point of merging, the current competitive state of the industry, the arguments that he found unpersuasive versus what was compelling, the reasoning on which he based his decision, and some strategic points from New T-Mobile’s vision for how it’s going to operate—which ultimately persuaded Marrero that it won’t harm wireless competition in the U.S.

Here are some of the key highlights, tidbits and testimony from the trial, as outlined in the judge’s ruling.

The trial ultimately came down to “competing crystal balls.” In his ruling, Judge Marrero wrote that the parade of conflicting expert opinions in a merger case like this one “virtually turns the judge into a fortune teller” assuming a “prophetic role” of deciding between the “competing crystal balls” offered by both sides.

“The parties’ costly and conflicting engineering, economic and scholarly business models, along with the incompatible visions of the competitive future their experts’ shades-of-gray forecasts portray, essentially cancel each other out as helpful evidence the court could comfortably endorse as decidedly affirming one side rather than the other,” he wrote, going on to say that “lacking sufficiently impartial and objective ground on which to rely,” he turned to “another evidentiary foundation more compelling in this court’s assessment then the abstract or hypothetical versions of the relevant market’s competitive future.”

Since dueling experts cancelled each other out, the judge relied on individual and corporate behavior—before the trial, and during it.

Marrero called behavior “especially relevant and compelling,” particularly the “plausibility and persuasiveness of particular witnesses’ trial presentations based on various behavioral guideposts.” He wrote that he had “ample occasion to observe the witnesses and assess their credibility and demeanor on the witness stand” and said that “behavioral drives and motivational forces … serve to actuate as well as to restrain personal and business practices. Hence they can function as a forecasting device, providing the court substantial guidance about how the corporate officers and companies involved in the case are likely to conduct themselves under particular market conditions prevailing after a merger.”

Marrero rejected the state AG’s arguments on three points. He was not persuaded that the post-merger future the AGs outlined was “sufficiently compelling” in its argument that New T-Mobile would pursue anti-competitive behavior post-merger that would result in higher prices or lower quality for mobile customers. He didn’t agree that a standalone Sprint would be a strong nationwide competitor. And thirdly, the court did not credit the argument that Dish “would not enter the wireless services market as a viable competitor nor live up to its commitments to build a national wireless network, so as to provide services that would fill the competitive gap left by Sprint’s demise.”

T-Mobile US’ success has its roots in the AT&T merger that fell through. T-Mobile US has been courted numerous times and under various circumstances negotiated a massive “break fee” with AT&T if that merger didn’t go through: $3 billion in cash, $3 billion in spectrum and a roaming agreement that allowed T-Mobile US customers to use AT&T’s network in areas that T-Mobile US’ network didn’t reach at the time. (In the Sprint/T-Mo deal, there been agreement on a four-year roaming agreement that would go forward if the merger did not.) When the merger failed in late 2011 due to regulatory skepticism, T-Mobile US capitalized on that windfall. In 2012, it brought on a new leadership team that included CEO John Legere and COO Mike Sievert (who will be taking over as CEO once Legere departs from that role on April 30), and thus its Uncarrier strategy was born. Those resources helped convince parent company Deutsche Telekom to put up $40 billion for T-Mobile US to invest in its network, which resulted in excess capacity that enabled T-Mobile US to lower its prices.

The four national MNOs really don’t have viable competitors, and the mobile virtual network operators that they host don’t do much in terms of constraining their pricing and competitive practices. One of the debates during testimony was whether MVNOs should be attributed market share, or that their customer bases should be counted as part of their host network(s). Merraro ultimately agreed with the state AGs that MVNOs aren’t independent competitors and “could not restrain the pricing behavior of MNOs to any truly significant degree”, both because they have such a small share of the market and because the terms under which they operate are controlled by the MNOs from whom they lease network access.

The ruling cited figures that one-third of all new subscribers since 2018 have gone to cable MVNOS: Comcast’s Xfinity Mobile, Charter’s Spectrum Mobile and Altice Mobile. But they still have a combined market share of less than 2%; Comcast only has about 2 million wireless lines in a market of more than 300 million lines. There was testimony that there’s no evidence of MNOs altering their pricing or service in response to cable MNOs, and the ruling also noted several examples of just how deeply MNOs affect MVNOs’ ability to compete for customers: Comcast’s MVNO agreement only allows it to offer wireless services as part of a bundle that includes its non-wireless services, not standalone wireless plans; Verizon also limits Xfinity Mobile’s ability to offer unlimited plans. Meanwhile, Sprint’s MVNO agreement with Altice requires Altice to pay Sprint every time a customer switches from Sprint to Altice, although the arrangement is meant to “eventually become reciprocal.”

Stay tuned for Part 2, coming tomorrow.