The court ruled that the Virginia anti-spam law's prohibition of header falsification constitutes an unconstitutional infringement of the right to anonymous political and religious speech, suggesting that it would have been acceptable of it was limited to commercial speech.
The court's decision was predicated on the assumption that header falsification is a necessary requirement for anonymity, but this is a faulty assumption. All that is needed for anonymity is the omission of identity information that leads back to an individual, not the falsification of headers or identity information. That can be done with remailers, proxies, and anonymously-obtained email accounts, with no header falsification required. I previously made this argument in more detail in response to the arguments given by Jaynes' attorney in the press.
I also disagree with the court's apparent assumption that commercial speech is deserving of less protection than religious or political speech. What makes spam a problem is its unsolicited bulk nature, not its specific content.