Just a further data note. Canada has a system called Medicare; it’s actually quite a lot like US Medicare, but less open-ended and more serious about cost control. Here’s Canadian spending on health versus US spending, both as percentages of GDP:

OECD Health Statistics

Hmm. Canadian Medicare looks pretty sustainable, especially as compared with the US system, which has much more private insurance.

Now, Canadian health care isn’t perfect — but it’s not bad, and Canadians are happier with their system than we are with ours.

So anyone who tells you that Medicare as we know it — a single-payer system that covers everyone over a certain age — is unsustainable is ignoring the clear evidence that other countries somehow manage to make similar systems quite sustainable.