It turns out that there are multiple nations able to run persistent deficits, and several have run bigger deficits relative to the size of their economies than we have. Britain, which has the deepest deficits, used to own a globally dominant currency — but the pound sterling stopped playing any important international role generations ago. The Australian dollar and the Canadian dollar have never been widely used outside their issuing nations.

So where does the idea that dollar dominance gives us a special ability to run deficits come from? I guess it’s just something that sounds as if it should be true, which I’ll come back to in a minute. But first, are there any other ways in which America gains special advantages from the dollar’s dominance?

Well, it’s possible that the worldwide use of the dollar creates the perception that dollar bonds are safe assets, so that America can borrow more cheaply than other nations. It’s hard to tell, because there are multiple factors affecting interest rates — and U.S. borrowing costs are not, in fact, noticeably lower than those of other advanced countries. If there’s any effect, however, it must be small. I won’t go through the arithmetic, but I can’t see any way that, considering all this together, dollar dominance is worth more to America than a fraction of 1 percent of G.D.P.

Why, then, are people making such a big deal over the possible end of dollar dominance? The answer, I believe, is that global currency issues come across as glamorous and mysterious, so people imagine that they must be important — and yes, some people like to talk about them because they think it makes them sound sophisticated. You have to actually work with the numbers to appreciate how little is really at stake.

Which means that I’m almost reluctant to add that reports of the dollar’s coming demise are also probably greatly exaggerated. The aforementioned paper by Gopinath and Stein offers a detailed analysis of one channel through which the dollar maintains its dominance, adding to a long literature that includes, among other things, some old papers by yours truly. The bottom line in most of this analysis is that the dollar is widely used because it’s widely used — that all of the various roles the dollar plays create a web of self-reinforcement, keeping the dollar pre-eminent.

The point is that tugging on one or two strands of this web isn’t likely to cause it to unravel. Even if some governments express a desire to see payments conducted in other currencies, it’s not at all clear they can make that happen, since we’re mostly talking about private-sector decisions. And even if they can make partial de-dollarization stick, all the other advantages of the dollar as a banking and borrowing currency will remain.

So ignore all the dollar doomers out there. Or better yet, consider what their hyping of a nonissue says about their own judgment.