It's definitely an over-reach. If they can force a company to change a product for this, then what's to say they can't slowly extend this precedent to all sorts of abuses of power.
There was a doctor's draft in the 50's, there was a more recent general "health care workers" selective draft but I'm not sure where it exactly stands.
Basically what Obama can do is issue a requirement to register with the Selective Services Administration as a threat failure to do so can incur heavy fines on each Apple employee. Once they are registered they can draft any engineer they need into military service and order them to do so, if they refuse they can be court marshalled. https://en.wikipedia.org/wiki/Selective_Service_System
This ofcourse will never happen, the most extreme case was under Truman and it was an ultimatum with an apparent executive order drafted but that was enough to bring the steel industry to it's knees and to the table.
The funny part is that if anything even remotely extreme happens we might start to see the seeds of the "2nd American Revolution" the one from so many dystopian novels where the world is ruled by corporations Apple, Google, Microsoft and the likes have enough power to seed the "corporate congress" :)
As far as I know there is not requirement for an act of congress to actually draft people under the SSA and for anything else a presidential order is sufficient.
To be rather obtusely specific, the FBI has not requested a change in product or even the design of a new product from Apple. I'm sure the FBI was well aware of the subsection of the US code the article is referring to which is why the request was framed as a "one-off tool" to help in an investigation, not a new product, and it's why the FBI itself is not saying it can require Apple, but rather that a court of law is saying Apple has to.
Again, this is nitpicking and IANAL, but the limitations section [1] is pretty clear that law enforcement itself cannot impose any requirement as to...
[...]require any specific design of equipment, facilities, services, features, or system configurations to be adopted by any provider of a wire or electronic communication service, any manufacturer of telecommunications equipment, or any provider of telecommunications support services; or[...]
The request being made isn't really covered by the limitations here. While I have full confidence that the end-game of this case for the US government is to add an exception for the creation of "one-off" tools, I don't think that the FBI's request is actually covered by this limitation.
The authority of the request doesn't come from law enforcement, it comes from a court, fulfilling the intended limitation that law enforcement can't dictate the design of communication technology for its own purposes.
Likewise, while a product of sorts is being created in the form of a law enforcement tool, the FBI isn't actually asking for this to be implemented in the product itself or requiring that Apple make it the standard either.
Furthermore, the entire section is discussing the ability to monitor, capture, and terminate communications, not talking about software or hardware itself, which his shared by the statement released by the FBI. [2]
Again, cannot stress that I am not a lawyer, but I think the interpretation on CALEA is fairly sound - it's not applicable as the purpose of the section being referenced is not relevant to the request being made. I do think that the request is still wrong regardless of any reasons put forth by the FBI and that it sets a horrible precedent, but this article (and by extension Apple's lawyers) are arguing a weak point using CALEA.
[1] - https://www.law.cornell.edu/uscode/text/47/1002
[2] - https://assets.documentcloud.org/documents/2755290/2016-03-1...
edited for clarity purposes
The fact that the FBI requires Apple to vouch for it as an iOS product makes the "not-a-product" argument harder to maintain. (Also weakening the argument: the applicability of nearly the same software to replace the OS on an unlimited number of iPhones that the FBI may introduce later, or if leaked, a large number of iPhones in the wild.)