(Bloomberg Opinion) -- Crises tend to widen fault lines that already exist. The Covid-19 pandemic has been no exception. Before the virus hit, the unbalanced nature of recent economic growth was already straining federal structures around the world, from the U.S. to India to Europe. The current crisis threatens to open new disagreements and deepen old ones — and transform some political entities beyond recognition.

This isn’t just a question of how central governments should distribute revenues and aid, although in most cases that’s the matter at hand. When Senate Majority Leader Mitch McConnell suggested that he’d rather see “blue states” go bankrupt than have the federal government bail them out, he wasn’t making only a crass political calculation. He legitimately didn’t want states to receive aid if he felt they had overspent on, say, pensions.

He raises a fair point: How, in this crisis, should the federal government fairly deal with states that hold completely different visions of what government is and what it should do? Why should states that are so allergic to government that they would reject even Medicare expansion funds agree to finance states that have readily taken on debt to pay pensions?

Of course, there’s an easy retort to that argument, summarized by the former U.S. Attorney for the Southern District of New York, Preet Bharara: Many of those populous and economically vibrant “blue” states are already providing more than their share of federal revenues. “I, too, am sick and tired of subsidizing Kentucky,” Bharara said, referring to McConnell’s home state.

The irony is that, across the world, it is these wealthier, more globalized parts of federal systems that have been hit hardest and earliest by the pandemic. The virus travelled across the world in airliners and cruise ships, carried by tourists and traders. Rich northern Italy, not the southern provinces that it has long subsidized, became the grim example of how deadly the new coronavirus could be. New York is the epicenter of the virus in the U.S., not deep-red states such as Kentucky.

A lack of solidarity at moments like this will be remembered. The European Union will at some point have to deal with its failure to support Italy when that country was at its most vulnerable. Whatever deal the EU’s leaders finally cut, the fact is that when northern Italy’s health system was overloaded, no trains of medical supplies and doctors crossed the Alps to help. European Commission President Ursula von der Leyen has admitted, “too many were not there … when Italy needed.” That failure will cost the taxpayers of northern Europe – and it should. If money isn’t a cure for hurt feelings, big intra-regional transfers are therapeutic at least.