"As has been pointed out many times, it isn't mathematically or technologically possible to build a backdoor into encryption that is completely exclusive to a select set of people, and can't be found and exploited by others."
As a politician, you can wish for a lot of things, but if it is mathematically impossible, it is. You cannot put legal requirements on using time traveling to prevent crimes either. Sci-Fi is Sci-Fi. Math is math.