1. A cell phone is (and remains) the best surveillance device ever conceived.
2. Apple is legally, morally and practically justified in opposing the order.
Your carrier has a perfect record of your location 24/7 going back years. Everything you do on a smartphone uses the internet and is the opposite of anonymous.
It’s trivially easy to physically locate any person or service you interact with. Every service you use (Facebook, Google, Skype, etc.) keeps **exhaustive** records of everything (messages / searches / calls / etc. ). Your phone now backs itself up automatically (including photos).
What can you actually do on your phone that **only** happens on the phone? Almost nothing. Even a simple note will be saved to the internet.
All of this data is fully accessible to law enforcement. Carriers and services have special help desks for this purpose. Often they do not require a subpoena under a law called “Communications Assistance for Law Enforcement Act (CALEA)”.
So, what exactly does the FBI want? The FBI would like to use San Bernardino as leverage to force Apple to make it easy for them to search phones again. That’s it.
Law enforcement got a free ride on searching phones due to court rulings that they are not subject to 4th amendment protection and searches do not require a subpoena.
iPhones before 2015 (and most Androids still) can be plugged in to a device (from China!) and all the data is “sucked out”. That’s very helpful if you’re the FBI but unfortunately these devices are **widely** available and heavily used by criminals.
Are you happy to keep your credit card details (ApplePay) on a phone if some thief can “suck out” those details in 2 seconds flat? Not likely.
The back door the FBI wants doesn’t exist on recent (more secure) phones, it can’t safely exist (remember the the TSA luggage key?) and is actually not even necessary. They can and do get 99% of the same data via other means.
The only way to ensure security is to never create a way to break it. Once a back door is created for law enforcement a huge wave of criminal effort will be unleashed to find, buy, or bully (think China) access to it.