Irrational exuberance and the terrible hangover. Lehman Brothers and Merrill Lynch both bit the dust yesterday, the worst day for the U.S. financial sector since the Great Depression. In the wake of Washington’s takeover of Freddie and Fannie and the collapse of Bear Stearns, the towers of finance capital are more than a little shaky.

Black Monday showed, for those who needed the lesson, that the kind of people Stephen Harper thinks are so good at running the world are not only greedy, they’re world class incompetents.

Harper and his pals, south and north of the border, believe in the wondrous power of de-regulated capitalism to make the economy soar by getting stale, old government out of the way. That is, of course, until the new financial instruments they invent, designed to turn billions of sow’s ears into silk purses, land them in big trouble. Then they scurry to government, quaking with fear, begging for the handouts their friends in office are only too happy to provide. Harper will use the financial crisis to reward his corporate friends and punish the rest of us.

We saw some cracks in the structures of capitalism yesterday. The shafts of daylight that came through teach people that there’s nothing wondrous or all-powerful about the system. Now’s the time to get out radical ideas about how to restructure our economy in the interests of wage and salary earners and how to take control of our petroleum industry out of the hands of Big Oil.

That needs to be the subject until election day.