Did Lehman's collapse start the crisis?

Two very reputable economists from Chicago, John Cochrane and Luigi Zingales suggest that the true cause of the crash probably has more to do with the TARP authorization...as they eloquently state...

In effect, these speeches [about TARP] amounted to "The financial system is about to collapse. We can't tell you why. We need $700 billion. We can't tell you what we're going to do with it." That's a pretty good way to start a financial crisis.

HT: Greg Mankiw