Now, in fairness we have to say that the United States was far from being the only nation in which banks ran wild. Many European leaders are still in denial about the continent’s economic and financial troubles, which arguably run as deep as our own  although their nations’ much stronger social safety nets mean that we’re likely to experience far more human suffering. Still, it’s a fact that the crisis has cost America much of its credibility, and with it much of its ability to lead.

And that’s a very bad thing.

Like many other economists, I’ve been revisiting the Great Depression, looking for lessons that might help us avoid a repeat performance. And one thing that stands out from the history of the early 1930s is the extent to which the world’s response to crisis was crippled by the inability of the world’s major economies to cooperate.

The details of our current crisis are very different, but the need for cooperation is no less. President Obama got it exactly right last week when he declared: “All of us are going to have to take steps in order to lift the economy. We don’t want a situation in which some countries are making extraordinary efforts and other countries aren’t.”

Yet that is exactly the situation we’re in. I don’t believe that even America’s economic efforts are adequate, but they’re far more than most other wealthy countries have been willing to undertake. And by rights this week’s G-20 summit ought to be an occasion for Mr. Obama to chide and chivy European leaders, in particular, into pulling their weight.

But these days foreign leaders are in no mood to be lectured by American officials, even when  as in this case  the Americans are right.

The financial crisis has had many costs. And one of those costs is the damage to America’s reputation, an asset we’ve lost just when we, and the world, need it most.