The full regulatory approval process for the Comcast/TWC merger has months left to go, but we’re getting down to the wire on one part of it: the deadline for public comments is Monday. Our colleagues down the hall at Consumers Union, the advocacy arm of Consumer Reports, have now officially asked the FCC to block this thing, and with good reason.

In their petition (PDF), Consumers Union sets out their arguments for why allowing Comcast to buy Time Warner Cable would hurt consumers. In a word, it’s all about competition, and the near-complete absence of it.

1.) Making Comcast bigger reduces other pay TV companies’ ability to compete. Sure, sure, Comcast and TWC don’t comepete geographically — but that doesn’t mean anyone else does, either. The lack of competition, combined with Comcast’s sheer size, gives them both the ability and the incentive to mess with other pay TV providers’ access to the content they own.

2.) A post-merger Comcast will have enough leverage to stifle online competition. Call this the Netflix problem. Content isn’t just for cable and broadcast networks anymore; it’s from online services, too. And by letting traffic bottleneck or trying to keep subscribers using their set-top tech, Comcast can keep consumers in their ecosystem… and lock the new tech guys out.

3.) The bigger Comcast gets, the more it controls what content viewers can see — and can lock out diverse content. It’s not just cloud-based, online, or streaming services that Comcast can control access to. It’s good old TV, too. Post-merger, Comcast would be the cable provider for 16 of the top 20 media markets in the country. They would have power to carry or to decline to carry programming to over 30 million consumers. Spanish-language channels in your city not willing or able to pay skyrocketing carriage fees? Too bad for viewers.

4.) When there’s no competition, consumers get rotten service. Everyone hates their cable companies’ customer service, but they put up with it because there’s nowhere else to go. Just this month, we’ve heard and seen several recordings that show just how bad bad can be. But if Comcast is the only internet provider in town, they have no reason to get better.

Delara Derakhshani, policy counsel for Consumers Union, said, “This mega merger would give Comcast unprecedented power to raise prices, limit choices, and stifle competition, which would seriously hurt consumers.” She continued, “If this deal goes through, we can expect to be hit with more skyrocketing bills and worse service as Comcast gains even more control over what we see online and on TV. The two companies have failed to demonstrate how the merger would serve the public interest. The benefits they claim are overstated, or elusive, or don’t depend on a merger, and they are far outweighed by the harms.”

If you want to file your own comment with the FCC, they’re taking them through August 25.

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