Canadians think of themselves as model global citizens, whether training troops in Iraq or settling refugees at home. That civic-minded spirit has now spread to economics, as Canada pursues a mix of monetary and fiscal policy that helps the world as much as itself.

Last month, Prime Minister Justin Trudeau’s Liberals introduced a budget that sharply boosts spending on a raft of initiatives from infrastructure to social benefits. Because of that fiscal stimulus, the Bank of Canada has refrained from cutting interest rates, helping send the Canadian dollar sharply higher.

The higher dollar will be a drag on Canada’s trade sector, diluting the budget’s stimulative impact. But Canada’s loss is the world’s gain. In fact, Canada is faithfully executing the formula that finance ministers and central bankers from the top 20 economies agreed to pursue at their just-concluded meetings in Washington: namely, rely less on monetary and more on fiscal policy to rejuvenate growth. The problem is that Canada is virtually alone in being both willing and able.

The global economy today resembles what game theorists call a collective action problem. This is a situation where countries will end up worse off by pursuing their own interest than by cooperating. Central banks in the eurozone and Japan have cut interest rates into negative territory, for instance, in what others claim is an attempt to cheapen their currencies to bolster exports and inflation.

A new paper by Gauti Eggertsson and Neil Mehrotra of Brown University and Larry Summers of Harvard University warns that such actions become a zero-sum game in “secular stagnation,” when interest rates are near zero and central banks can no longer restore full employment. Instead, easier monetary policy works mostly by bolstering exports and dampening imports, inflicting “negative externalities”—collateral damage—on a country’s trading partners.