The administration's reasoning behind the decision to postpone the implementation of the Obamacare employer mandate is simple: It is purely political.
They are trying to minimize the impact of this unread monstrosity of a law until after the election. But it begs the question: Since when can a president grant waivers of a law at will and decide what parts of the law to enforce?
It is the same with our existing drug and immigration laws. They are simply ignored when deemed inconvenient.