This was raised and discussed in another thread and I believe this to be the case. Walt Mossberg, a pretty well known verge reporter who wrote one of the articles that was circulating a few weeks ago about the decline in Apple software, was discussing this on his podcast.
The idea that actors move forward with a specific case was new to me, but I obviousloy never thought much about it and it seems pretty intuitive when considered. Roe v. Wade and the Rosa Parks case were raised in the other thread as well as, IIRC the Brown v. Board of Edu.
What happens is that the prosecution or another actor can Appeal to the supreme court (or choose what case to prosecute etc.) with the ultimate goal of timing sentiment, finding the perfect array of facts and discovery, and having everything align perfectly. They then push up to the supreme court with the best chance of getting a binding ruling that would become defacto law.
In this scenario (and from here forward is my non-expert opinion) the data is probably in a best case scenario for the FBI slightly useful. However, not getting this data is pretty much meaningless. So they are likely to:
* Use public sentiment and the recent terrorist attacks as a catalyst for their demand (you quite correctly raised this point).
* The suspects are dead. So while they may not be guilty in the court of law, it is pretty obvious that they did it thus there is no risk of them being acquitted.
* Most evidence suggests a fairly lone wolf attack scenario, so if they were working with anyone the data would likely be on a computer or in call logs. Thus the minimal gov't gain which would be maybe mapping a name to some of the numbers.
* They have a successful narrative to frame and this coincided with a bill to limit encryption.
So yes. This was a strategic move. If John McAfee is to be believed, and on one hand he sort of fucking isn't, but on the other hand I actually do but mostly on faith, he and his team can successfully decrypt the phone.
He has publicly offered (possibly taking out an editorial but I did see the article at least) that he would unlock the phone for free if they would drop the case. Now, even if they gov can't get in (and they can), it isn't unreasonable to not give the phone to a suspected murder.
That said I think John McAfee and probably a few people on here could get in, so the tl;dr is ya they coming for that secure enclave.