The United States Department of Justice has filed its opposition to the AT&T - T-Mobile US merger on anti-trust grounds.
AT&T’s elimination of T-Mobile as an independent low- priced rival would remove a significant competitive force from the market
AT&T was pursuing the merger in an attempt to get T-Mobile's AWS spectrum to use for a bigger, better LTE 4G roll out.
(Probably smart that T-Mobile wasn't waiting on AT&T to get iPhone 5.)
This story is still developing and we'll update with more information as it comes in.
[Bloomberg, thanks Jack!]