Bruce Bartlett omits a rather significant pair of dates:

The history of anti-recession efforts is that they are almost always initiated too late to do any good. This chart, based on recession timelines from the National Bureau of Economic Research, shows the enactment of stimulus plans is a fairly accurate indicator that we have hit the bottom of the business cycle, meaning the economy will improve even if the government does nothing.

Of course, the two missing dates on that little chart are 1930 and 1934… and to argue that the existence of the stimulus package demonstrates that the contraction is ending strikes me as more than a little myopic.