OBAMACARE'S federal exchanges have gotten off to a rather rocky start, compared to the state-run exchanges, which are apparently doing much better. But one thing you can say about Obamacare's health exchanges, whether federal or state-run: they exist. The websites are up, and you can visit them. The people who build and operate them are going to work and getting paid. Which, in the current shutdown, is more than you can say for a lot of the government.

For example, over at NASA, a crew of about 15 physicists, engineers and several grad students are supposed to be working on the Primordial Inflation Polarization Explorer (PIPER), a precision instrument to measure the polarisation of the Cosmic Microwave Background in order to test the inflation theory of the origins of the universe. The researchers need to create new sensors that can detect the polarisation of variations of one to ten nanokelvins in the 2.7-kelvin Cosmic Microwave Background. Then they're supposed to put the instrument on a 100-metre balloon and send it up from various sites in the northern and southern hemispheres. But they're not working on that! They're twiddling their thumbs and doing nothing of any use to anyone.

In fact, you can't even access their website to read about all the fascinating work they're not doing, because that's shut down too. Not that things were going all that well before the shutdown; the sequester was already wreaking havoc with the working lives of the scientists at NASA, like those at NIH, the CDC and the rest of the government's research institutions. But the shutdown has added insult to injury: while some of the people working on PIPER are NASA employees, who (by executive order) will be reimbursed for their lost weeks of work after Congress approves spending authority again, others are private contractors, and there's little chance they will be paid for their lost weeks at all.

The reason NASA, NIH, the CDC and so forth are shut down, while Obamacare is going ahead at full speed, is that their spending is largely classified as part of the discretionary budget, while Obamacare, like all other entitlement programmes, is mostly part of the mandatory spending budget. Mandatory entitlement spending, such as Social Security, Medicare, Medicaid and Obamacare, doesn't need annual congressional approval to go ahead. Its funding is guaranteed as part of the legislation that creates it. This is the nature of social insurance programmes; nobody would sign up for a health-insurance plan that said "Medicare will pay for your cancer treatment, provided the House of Representatives votes to pay for it that year", and no doctor would perform the therapy if payment were conditional on the government's discretionary budget that year. So while the physicists and engineers at PIPER are idling, the programmers labouring on Healthcare.gov are working overtime and getting paid for their troubles.

Now, if you were thinking of going to work for the government, which of these institutions would you prefer to work for? The one that contracts you to build something fascinating and complex, but may mothball the project and stiff its workers arbitrarily, depending on how Ted Cruz is feeling next autumn? Or the one whose spending authority is guaranteed by law, unless Congress can get it together to actually change that law? I know where I'd rather be. It's demoralising to have your projects blown up halfway through and to live in a state of constant uncertainty about your own salary. And, indeed, the people who work on the inspiring, fascinating projects the government pays for out of discretionary spending, whether they're doing medical research grants for NIH, basic physics research for NASA, fighting AIDS in Africa for USAID, or what have you, are growing increasingly demoralised and leaving the field.

People like to joke that America's government is basically an insurance company with an army. The never-ending series of payment crises Republicans have concocted over the past few years are rendering this ever truer. Increasingly, entitlement programmes and defence are the only two functions the government can be counted on to actually pay for—and I'm not even sure about the latter.