Seems a no brainer to me.
States have limited resources. States must adhere to a balanced budget.
Contrast with the federal government with unlimited access to money.
The federal government has admitted that it can't pay for this health care 'marketplace', which would cost between $10 to $100 million per year in each state. Hence the necessity for each state to set up its own exchange, shouldering some of the costs.
The problem with that notion is that nowhere in the 2,700 page behemoth known as the Affordable Care Act, is it written that the states will be required to do so; the assumption being that the states would simply go along with the federal governments wishes.
Freedomworks, "State run exchanges, last hope against Obamacare"
Rather pompous, don't you think?
We (federal government) don't have the money to run the health insurance exchange so you (states) do it for us?
Because of this (lack of state run exchanges), the government cannot legally enforce the employer mandate "tax" on employers in a state that has not set up an exchange. Without the employer mandate, and without the exchanges to manage the insurance subsidies, ObamaCare falls apart.
That's a mouthful.
It also brings up this point.
With regard to the health insurance exchange, states have the power to say "We didn't build that".