Right now, the economic downturn is decelerating. It doesn’t mean the unemployment rate won’t go higher–it will–but despite today’s GDP number a number of indicators suggest the worst is behind us. Maybe.

Here’s the rub. The economy appeared to be doing better in the weeks leading up to the Lehman failure. Then Lehman went under, the global capital markets froze, and the domestic and international economies resumed their downward momentum.

Is the swine flu potential pandemic the global equivalent of a Lehman failure? The answer is not yet, but it could be. If it’s contained then the U.S. economy should continue to do slightly less worse in the months ahead. And in the current context that’s good news. But if the pandemic gets worse the global economy will take another drop down.