What US healthcare means for the world
I write this from New York, where commentators can talk of little else but President Obama's "make-or-break" speech on healthcare.
For the past month, the US airwaves have been filled with pictures of townhall meetings and demonstrations on health care reform across the country, with angry citizens begging the president not to embrace "socialised medicine", and turn America into Russia. As if.
The good news for the White House is that all that sturm und drang seems to have changed very little. According to the New York Times opinions on healthcare reform are pretty much what they were before the summer.
A CBS poll taken at the end of August found that 60% of Americans still support the idea of a government-backed alternative to private health insurance, compared with 66% in July. And 50% said they preferred Obama's ideas on health care to the Republicans' - down from 55%.
So much for the good news. The bad news is that the financial markets aren't the only part of the economy that can be led astray by human psychology. It can mess up the best laid plans for healthcare reform as well.
One of the big findings of behavioural economists is that people suffer from "status quo bias". They fear change and hold on to what have, even if what they have is pretty flawed.
We saw a taste of it in the UK this summer. No-one has a good word to say about the NHS - until it is threatened from outside, and we all suddenly decide it's the best health system in the world.
As James Surowiecki pointed out recently in The New Yorker, status quo bias is killing Obama's healthcare reform plans.
In the middle of the presidential campaign a year ago, a poll found that only 29% of likely voters rated the US health-care system good or excellent. But asked the same question last month 48% put it in the good or excellent category.
The only thing that's changed about US healthcare in that time is that voters have listened to months of debate over reform.
Should anyone outside the US really care about what happens? Here are two obvious reasons why we should - and one slightly less so.
The first is that healthcare reform is the most important policy goal of the president of the world's most important country. Win or lose, this battle is going to affect his ability to get other things done as well, some of them (like climate change) extremely important to the rest of the world.
Second, the US healthcare industry is roughly the size of the UK economy. It matters if an industry that size is going to be fundamentally reformed. And, given the rate of growth in healthcare spending right now - it may matter even more if it isn't reformed.
The third, less obvious, reason to care about the US healthcare system is that it has actually played an astonishing role in making the US the world's largest consumer in the past 20-30 years.
Between 1950 and 1980, personal consumption in the US was around 62% of GDP. But in the next 30 years it grew to nearly 70%, about 8 percentage points more than the OECD average.
We tend to think that rise was all due to a debt-fuelled spending spree on foreign-made cars and TV sets.
But the share of spending devoted to those kinds of physical goods actually fell sharply during that period, from 45% in 1980 to about 33%.
That was partly thanks to those things getting cheaper. But the main reason was the onward march of healthcare costs.
According to the US Bureau of Economic Analysis, healthcare costs now account for 16% of total private consumption, roughly double the share in 1975. And of course, government healthcare spending has risen hugely since the 1970s as well.
The bottom line is that America's very high level of consumption relative to other countries is a relatively new story, and it is almost entirely accounted for by rising healthcare costs.
Unlike other consumption, health care spending has even continued to rise since the US went into recession at the end of 2007.
Of course, health care costs have been rising elsewhere - in some cases even faster than in the US. But per capita health spending is still double the OECD average, and US healthcare spending is more than 17% of GDP - streets ahead of anyone else.
Critics say - with some justification - that Obama's plan will do very little to curb the growth in health care spending in the US. It may even make things worse.
You might also say it's up to Americans to decide what they spend their money on. We already know that the rest of the world cannot afford to rely on US consumers in future as heavily as they have in the past.
All of that's true. But if we want American consumers to have the money to buy much of anything at all, we probably want somebody - either President Obama or someone else - to change the status quo in American health.