Oberlander brings several lenses to bear on the problem. He describes how it was _not_ created as part of the New Deal, even tho it was desired at the time it was sacrificed due to resistance on the part of the AMA among others. When it was finally signed into law in 1965, its blank-checkedness was in part to get the AMA (and private insurers) to not resist too strenuously. Since then, changes in benefits have been minimal (this book does not cover the passage of Medicare Part D, just the electoral posturings leading up to it). While a very popular program, and while some survey wordings indicate people would pay more for the program, its trust fund structure has subjected it to numerous fiscal crises which provided opportunities to restructure the program's administration. Most of this occurred in a bipartisan fashion out of public view, however, the addition (and rescinding) of catastrophic insurance and then the addition of HMOs were all the result of increasingly polarized party politics and competing visions for Medicare's future.
There were several surprises to me. First and foremost, if this guy is to be believed and assuming I understood him correctly, all of the major savings wrung out of Medicare over the decades have been directly the result of it becoming more and more single-payer like and more and more regulated -- and some of these stepwise changes have occurred simultaneously with "marketlike" reforms a la the Contract on America's addition of HMOs. We're really a lot more like the Europeans and other developed nations than we think we are. The difference is not whether we can run a single-payer, highly regulated program in a cost-controlled, satisfactory fashion; the question is who do we choose to cover under that program.
The second surprise was the consistency of opposition to Medicare by politicians like Bob Dole, who opposed it in 1965 and tried to dismantle it three decades later. There are some priceless quotes in this book from people like Newt Gingrich, saying they expect Medicare to whither away as everyone switches to private insurers. Not likely, and furthermore, anyone who gives this any thought at all would realize that letting the privates cherry pick will just raise costs overall with no meaningful increase in benefits across the board. Utter insanity.
The third surprise was how come Medicare covers what it does and doesn't cover what it doesn't (specifically, why a prescription drug benefit was so slow in arriving, and crappy when it did appear, and why there still isn't a long-term care benefit under Medicare). The people who crafted Medicare at the beginning really hoped and expected this to be a wedge that became national health insurance that would ultimately include long-term care, prescription drugs, etc. But because cost containment was always so enormously problematic, benefits creep didn't happen, much less major extension of benefits to new categories of people/new categories of treatment (with the exception of end stage renal disease; that was an interesting little anecdote as well).
It's academic. It's wonky. It lacks narrative thrust, even tho it is mostly organized chronologically. But it is fantastically good. Should you read it? If you're interested in politics in this country, this ought to be on your list somewhere.