The Greek fiscal crisis erupted five years ago, and its side effects continue to inflict immense damage on Europe and the world. But I’m not talking about the side effects you may have in mind — spillovers from Greece’s Great Depression-level slump, or financial contagion to other debtors. No, the truly disastrous effect of the Greek crisis was the way it distorted economic policy, as supposedly serious people around the world rushed to learn the wrong lessons.

Now Greece appears to be in crisis again. Will we learn the right lessons this time?

What happened last time, you may recall, was the exploitation of Greece’s woes to change the economic subject. Suddenly, we were supposed to obsess over budget deficits, even if borrowing costs were at historic lows, and slash government spending, even in the face of mass unemployment. Because if we didn’t, you see, we could turn into Greece any day now. “Greece stands as a warning of what happens to countries that lose their credibility,” intoned David Cameron, Britain’s prime minister, as he announced austerity policies in 2010. “We are on the same path as Greece,” declared Representative Paul Ryan, who was soon to become the chairman of the House Budget Committee, that same year.

In reality, Britain and the United States, which borrow in their own currencies, were and are nothing like Greece. If you thought otherwise in 2010, by now year after year of incredibly low interest rates and low inflation should have convinced you. And the experience of Greece and other European countries that were forced into harsh austerity measures should also have convinced you that slashing spending in a depressed economy is a really bad idea if you can avoid it. This is true even in the supposed success stories — Ireland, for example, is finally growing again, but it still has almost 11 percent unemployment, and twice that rate among young people.

And the devastation in Greece is awesome to behold. Some press reports I’ve seen seem to suggest that the country has been a malingerer, balking at the harsh measures its situation demands. In reality, it has made huge adjustments — slashing public employment and compensation, cutting back social programs, raising taxes. If you want a sense of the scale of austerity, it would be as if the United States had introduced spending cuts and tax increases amounting to more than $1 trillion a year. Meanwhile, wages in the private sector have plunged. Yet a quarter of the Greek labor force, and half its young, remain unemployed.