> To argue against that, you'd need to claim that precedent makes it easier for the later court to fail.
No, I'm arguing that incrementalism means the court doesn't have to fail (as a court) - the follow-on steps that I outlined and you found perfectly acceptable will not stop wherever you personally think they will, nor have I outlined (or even imagined) all the incrementally creative applications of this case that will likely follow. I'm also arguing (which you didn't counter) that this case lays the groundwork for the FBI to request _new_ products from companies.
> This is the part that doesn't follow from precedent. Giving over control of the tool to the FBI who could use it without a warrant is novel, and would require a judge to justify it.
I was being brief to illustrate, not to set a literal expectation of progression; I'm not here to present an argument for court. Giving the FBI control over the tool could be argued at any point in the very long lifetime of this decision, be it tomorrow or years from now. Perhaps after the courts have decided to allow for multiple devices or when suspect X is holed up for weeks in their cabin eating pizza and playing candy crush and the FBI cannot reach them by normal investigative means.
> Pure tinfoil material here.
Perhaps. Consider the probable value of the data on the phone beyond what's already available externally. Consider that the FBI could have simply requested Apple provide the data on the phone instead of specifying the mechanism and thereby creating precedent that they can compel a company to create something new. Consider that, in spite of generally dim views of the FBI's technical capabilities, the FBI usually provides sound, conservative advice with regard to electronic evidence (as a forensic analyst I've been party to a lot). Consider that over the past year+ the FBI has been protesting with little effect in congressional hearings that $todays_crime_buzzword are "going dark", that technology companies need to cooperate with them, that "securely insecure" (my words) systems are possible if created "at the design level" (not my words). They were nearly shouted down in those hearings. Consider the subsequent public visit the FBI and others made to Silicon Valley, extending an olive branch and returning effectively empty-handed.
Then consider that this case, involving an older and still-vulnerable version of a technology the FBI has been warning about, suddenly falls into the FBI's lap. It's politically and emotionally charged, it involves terrorists - they can ask for the world and society will rubberstamp it "because terrorists."
So the FBI asks for something small but very specific, and in doing so "happens" to set a precedent that they can compel companies to create a new product to bypass the very security measures they've been arguing vehemently against. Do you really think that's accidental?