WHAT does Paul Ryan think will happen if America fails to set its fiscal house in order? This:

Unless we change course, we will have a debt crisis. Pressed for cash, the government will take the easy way out: It will crank up the printing presses. The final stage of this intergenerational theft will be the debasement of our currency. Government will cheat us of our just rewards. Our finances will collapse. The economy will stall. The safety net will unravel. And the most vulnerable will suffer.

Is hyperinflation really what's in store if America keeps living beyond its means? Neil Irwin of the Washington Post doubts it. First of all, he argues, the costs of Medicare and Social Security, the insatiable monsters of the budget, are either subject to inflation or indexed to it, and thus inflation wouldn't really help. For this reason, Mr Irwin writes, "inflation wouldn’t offer Congress much of a way out of its deficit problems; indeed, it could make them significantly worse." So there would be little temptation to inflate.

I confess to not fully grasping the logic of this, though it is certainly interesting to glimpse Mr Irwin's assumptions about what would and would not remain fixed should the Fed set the presses to warp. The value of the currency evaporates, but statutory inflation adjustments remain!

I suspect part of the problem here is that Mr Irwin imagines that Mr Ryan is imagining relatively high but manageable 1970s-style inflation—8%, say—while I, having spent most of my professional life around Ayn Rand-loving deficit hawks like Mr Ryan, imagine that Mr Ryan really is imagining a full-on Zimbabwean monetary calamity, as fantastic as that may seem. He really thinks the stakes are really high, not just that moderate inflation may nibble unjustly at the nuts we've stashed for our golden years.

The full story in the event of a hyperinflationary catastrophe is far too complex to predict, but it's fun to think about how it might go. Here's my very rudimentary sense of things. Why would America, if "pressed for cash", as Mr Ryan puts it, start financing its spending through rapid inflation? Probably because the cost of issuing new debt (currently a relatively cheap option) had become too dear. But then the Treasury's credit rating would tank even further, and the cost of borrowing would become really prohibitive, forcing the government to finance new spending mainly through new revenue. But runaway inflation would quickly kill the real value of any taxes collected, no matter how high rates are jacked up. So, assuming Americans won't contemplate anything like selling the Grand Canyon to a consortium of sheiks (in euros, or gold-pressed latinum), it would become simply impossible to finance Social Security and Medicare at current real levels. There is, sorry to say, no legal entitlement to social-insurance transfers, so the government would violate no law by backing out of its promises. Should the hallowed institutions of the American state somehow manage to survive a hyperinflationary cataclysm, presumably Congress would simply scrap the inflation-indexing of Social Security, and/or continue to mail cheques that America's seniors and health-care providers will find good mainly for kindling, or a laugh. That's how the safety net unravels. There's no way to continue to pay for it, so it stops being paid for, and so it goes away.

Mr Irwin, imagining a rather less grisly scenario, suggests that "any politician who tried to freeze Social Security (particularly at a time of high inflation) would surely find gray-haired armies of angry seniors in their office making their dissatisfaction known". I'd be more worried about armies of armed Army personnel making their dissatisfaction known.

Mr Irwin goes on to argue that, in any case, we can trust the Federal Reserve to not get carried away. Not to say that it hasn't. Mr Irwin acknowledges that it has happened "as recently as the 1970s, when Fed chair Arthur Burns allowed inflation to get out of control in no small part due to political pressure from the Nixon administration." Furthermore, "An acquiescent central bank is crucial to understanding the inflation episodes ... in Germany, Zimbabwe, and Italy".

But that won't happen here, now! Why not? Because "a lot has changed since Arthur Burns’s time, and the idea that a central bank has not just the power, but the responsibility to prevent inflation from getting out of control is deep-seated within the Fed and other central banks." That's it?

Either Arthur Burns was a pushover or he didn't know better or both. Suppose we really do know better now. Why assume we won't get another pushover? Actually, let's take it easy on poor Arthur Burns. The central variable isn't really the resolve of the central banker, but the nature of the "political pressure" applied. Suppose the children of members of the FOMC begin to disappear and the president says he has no idea what's going on but can imagine circumstances under which he might feel inclined to look into it?

My point isn't that Paul Ryan is on to something, and that failure to travel "The Path to Prosperity" will really have us pushing wheelbarrows of cash to the Piggly Wiggly. My point is that the system really is fragile, and really does depend on a handful of people in critical positions of power doing the right thing, even when it hurts. I don't happen to think we're in imminent danger of the sort of systemic failure of continence I imagine Mr Ryan imagines. I'm naive enough to suppose that portents of such a dire future would be already visible in interest rates and measures of inflation expectations, and they aren't. But I do think that there's something to be said for the idea that value of a government guarantee—of access to health care, or retirement security, or whatever—is only as good as the culture within which the government operates. If America's political culture turns out to be such that we are at last unwilling or unable to rein in deficit spending and shrink the debt, then we ought not be too confident that in a pinch our politicians and technocrats will be willing or able to nobly man their posts.