"The plaintiffs in both Pruitt and Halbig claim, correctly, that Obamacare forbids the administration to issue the law’s “premium assistance tax credits” in the 34 states that have refused to establish a health insurance “exchange.” The Pruitt and Halbig plaintiffs further claim that the administration’s plans to issue those tax credits in those 34 states anyway, contrary to the statute, injures them in a number of ways. One of those injuries is that the illegal tax credits would subject the employer-plaintiffs to penalties under Obamacare’s employer mandate, from which they should be exempt. (The event that triggers penalties against an employer is when one of its workers receives a tax credit. If there are no tax credits, there can be no penalties. Therefore, under the statute, when those 34 states opted not to establish exchanges, they effectively exempted their employers from those penalties.)"
If the Obama Admin fears the entire law could be struck down the knee jerk reaction would be to remove the penalty. With no employer penalty the plaintiffs would have no damages.
"Third, shortly after announcing it would effectively repeal the employer penalties until 2015, the administration wrote the Liberty, Pruitt, and Halbig courts to argue that the delay should (at the very least) delay the courts’ consideration of those cases. In Liberty, the Fourth Circuit rejected all of those claims."
What the removal of the penalties would do to the cost would be horrific from a budget standpoint, but Obama has never really been shy of trillion dollar budgets anyways.