The sweet spot of opposition to Obamacare has always been finding measures that are good politics, that actually help people, and that undermine the law. Grandfathering does all three. It has divided Democrats and forced the president to make a concession that was probably unimaginable to him two weeks ago. How much real difference it makes depends on how insurers and the states react, but it has the potential to keep even more people out of the exchanges and further undermine their long-term viability. (See our friend Jim Capretta here on why complaints from the insurance companies that they can’t possibly keep people on canceled policies are over-wrought.) In attempting to stem the panic of congressional Democrats, Obama has thrown the insurers who had bought into Obamacare under the bus, a move that itself could harm the law’s long term prospects. He has once again acted unilaterally and (presumably) lawlessly rather than going to Congress, but he has undercut his own spin that Obamacare is the immutable “law of the land” and in his press conference, admitted that many of the law’s failures are on him rather than the result of Republican sabotage. We’ll see now whether the president has at least stabilized his position on Capitol Hill. Regardless, a bad day for him and the law.