The lawyers that brief these cases bring in all possible ways to uphold a stature that they can think of. Conservative Justices will uphold a law on any grounds they can and defer to the legislative body.
If you note the dissents they were very respectful of the CJ.
When I saw Scalia go off in the Arizona case on Monday I figured Obamacare was going to be upheld, Scalia and the other conservative Justices respect the CJ and understand both his reasoning and his concern for the Court IMHO..