After decades of false starts and frustration, free market champions should be cheering— competitive marketplaces work in health care. And no matter what your opinion of Obamacare, you have got to admit, that's a good thing. It's now been about a decade since President George W. Bush enacted Medicare Part D — a competitive market for drug benefit plans with government set ground rules. Competing plans have to comply with benchmark regulations—for instance, they have to cover two or more drugs in each drug category—but otherwise, they are free to set their formularies, premiums, tiering arrangements and co-pays.