If you want an analysis of oral argument, see:
Aereo Oral Argument Annotated: The Good, The Bad and The Ugly | CIMC/Greenfield
(Warning, this is a full review of the justices comments during oral argument, so it's long.) Given the level of technological illiteracy exhibited during oral argument, I fear that technological misunderstanding is a bigger concern than I had hoped/expected prior to oral argument. I think politics are not likely to be an issue. (This is not in the domain of ideological issues.)
Nonetheless, based on the Justices' comments during oral argument, it appears most likely that there will be a majority for Aereo.
Some comments, regarding other statements above:
1) Aereo almost certainly could not operate if they needed to negotiate retransmission with broadcasters. For two decades, major broadcast networks have used retransmission consent for their owned and operated stations to force carriage of the rest of their cable networks as part of the channel bundle. They're not about to undercut their own business to license just their broadcast networks to Aereo. In other words, major broadcasters would probably refuse to license their signals to Aereo on anything even remotely resembling reasonable terms.
2) Retransmission fees aren't copyright fees. Cable operators don't pay copyright fees to retransmit local stations. Such is covered under the 17 USC 111 compulsory license for local retransmission of broadcast stations. (Operators pay just a minimum filing fee for local retransmission.) Copyright fees are applicable only for non-local retransmission, and then get paid into a fund to pay rights holders, not broadcasters. The broadcasters are complaining about retrans fees that are separate from copyright law, and which are not even at issue in the (copyright) case before the Court.
3) What would be activist would be for the Court to try to find Aereo's performances to be public performances. Though the result may be unsatisfying for some, the text of the law as it exists requires the conclusion that the transmissions are private performances. One must badly contort the text to reach a conclusion that the transmissions are public performances -- and attempting to do such would unavoidably create unintended consequences for a wide array of other technologies and applications, most notably, cloud storage and streaming technologies. These "good" cloud technologies cannot be separated from "bad" technologies like Aereo, except by creating new, arbitrary distinctions, with no basis whatsoever in the existing statute. If such is appropriate, it is the domain of Congress, not the courts, to create such new, arbitrary distinctions.
4) Even if the Court finds the performances to be public, it's quite clear from oral argument that they will provide guidance recognizing that Aereo qualifies as a cable system under the Copyright Act, so that they are entitled to the compulsory license for retransmission. But they still won't be subject to retransmission consent, because the Cable Act uses a different definition of cable system, that clearly excludes OTT providers like Aereo. (Note however that retransmission consent isn't an exception to copyright law. It's completely separate. And it doesn't apply to just cable companies. It applies to MVPDs (multichannel video programming distributors) generally. But Aereo doesn't fall within the current definition of an MVPD.)
5) Claims that Aereo's antennas obviously act as a single antenna are just that, claims -- and claims that aren't supported by the factual record. The broadcasters challenged the independent functioning of the antennas in district court, and they lost badly. This was not merely some technicality of law where facts had to be ignored. It's conceivable that the broadcasters could try again, but any claims that the antennas obviously can't function independently and still work should be understood as bluster, given the broadcasters failed to present credible evidence of such, even with access to the equipment to conduct their own testing.
6) The question of public vs. private performance doesn't even depend on whether there are individual antennas for each user. (Whether the DVR copies made are legal fair use probably does, but that isn't at issue in the current proceeding.)
The bottom line in this case is simple: the law clearly requires a conclusion that the transmissions in question are private performances. A finding otherwise will have significant, problematic consequences, not so much for Aereo (who ironically, will probably be able to reconfigure itself with the benefit of the compulsory license mentioned above) but for a lot of other entities.
If you believe that Aereo being legal is a problematic outcome, then you should be arguing/hoping for Congressional action to revise the law in a sensible fashion, not for judicial activism to elevate some sense of right and wrong over what the existing law actually says, and creating lots of unintended and problematic side-effects in the process.
