The post cites support from organized labor, expected to be crucial to winning Democratic support.
"In the end, opponents’ submissions are long on rhetoric and short on substance."
The public interest groups claim AT&T has previously resisted investing to improve capacity and deploy next generation wireless networks as competitor Verizon Wireless has done.
The groups argue AT&T shouldn't be rewarded by attaching its willingness to build out its network to the government's approval of the merger.
" 'Maximizing AT&T's wealth' is not, and never has been, a public interest benefit justifying any merger, much less a legally cognizable merger-efficiency that could justify increasing concentration in an already highly-concentrated industry," the groups state.
The filing also notes that under-served groups such as minorities and rural residents tend to rely on wireless broadband service to an even greater degree, and argue that their public interest should trump AT&T's interest "in expanding their bad service at high prices at the expense of competition."
The groups note AT&T will not offer T-Mobile's service plans to AT&T customers but will simply honor existing contracts until they expire or customers request an upgrade.
They ask the commission to deny the merger, referring to the telecom giant as a "well-chronicled price hiker and strong-arm tactician."