During the first half of this year, German and American political leaders engaged in an epic debate. American leaders argued that the economic crisis was so bad, governments should borrow billions to stimulate growth. German leaders argued that a little short-term stimulus was sensible, but anything more was near-sighted. What was needed was not more debt, but measures to balance budgets and restore confidence.

The debate got pointed. American economists accused German policy makers of risking a long depression. The German finance minister, Wolfgang Schäuble, countered, “Governments should not become addicted to borrowing as a quick fix to stimulate demand.”

The two countries followed different policy paths. According to Gary Becker of the University of Chicago, the Americans borrowed an amount equal to 6 percent of G.D.P. in an attempt to stimulate growth. The Germans spent about 1.5 percent of G.D.P. on their stimulus.

This divergence created a natural experiment. Who was right?

The early returns suggest the Germans were. The American stimulus package was supposed to create a “summer of recovery,” according to Obama administration officials. Job growth was supposed to be surging at up to 500,000 a month. Instead, the U.S. economy is scuffling along.