Today’s congressional hearing into the proposed AT&T/T-Mobile acquisition is over, and my colleague Stacey Higginbotham has a great recap here. As she notes, both companies’ CEOs “appeared to weasel out of attempts to get them to discuss confusing statements or get them to swear that prices would go down for consumers as a result of this deal.” But Stacey also points to the economic edge AT&T and Verizon have in operating their own landline networks, which other carriers pay to use to connect cellular towers to back-end systems. That’s an under-reported issue, and it’s one more reason why the feds should reject the deal — or at least for some very difficult concessions from AT&T.