I wonder if Senator Ben Nelson would care to repeat his requirements for voting for Obamacare. In this video he pushes back that he had been bought by the infamous Corn Husker Kickback. No, he didn't sell his vote but he had requirements and one of those requirements would meant no federal exchanges. The way Obamacare was produced with secret meeting and no committee hearings makes it impossible to divine the will of congress as defender of that flawed piece of legislation have attempted to do.
If the plaintiffs in Halbig v Burwell should prevail in the Supreme Court Obamacare mandates, both individual and employer, would be nullified in 36 states leaving only blue states under the Obamacare burden.