To The Economists R.A. "Doesn't mean a thing" doesn't mean a thing.
R.A. wrote " if America is any indication, tighter fiscal integration doesn't mean a thing if the people running the show at the federal level are short-sighted, provincial, and apt to choose grandstanding over good policy."
The post is, in general, excellent. However, the concluding sentence is clearly false. Your claim that US fiscal integration "doesn't mean a thing" asserts that automatic transfers from states with shrinking output to states with more rapidly shrinking output did not occur.
I think it is obvious that when you wrote "doesn't mean a thing" you assumed that the words didn't mean a thing, that the very clear definite and exact statement that the effect of fiscal union on the US state budgets is exactly zero, was merely an general expression of disapproval of the US Senate.
I think it would be better if The Economist recalled that words have specific meanings, and that the general feeling one has when typing them is not a guide to the accuracy of one's assertions.
In fact, the unemployment insurance system and Medicaid automatically transfer money to the budgets of worst hit states. The case that fiscal union made it not utter idiocy to use the same currency in all of the USA was not at all based on the assumption that the Senate would do anything in response to need, but rather based on the automatic transfers implied by existing programs.