As recently as three weeks ago it was still possible to argue that the state of the U.S. economy, while clearly not good, wasn’t disastrous — that the financial system, while under stress, wasn’t in full meltdown and that Wall Street’s troubles weren’t having that much impact on Main Street.

But that was then.

The financial and economic news since the middle of last month has been really, really bad. And what’s truly scary is that we’re entering a period of severe crisis with weak, confused leadership.

The wave of bad news began on Sept. 14. Henry Paulson, the Treasury secretary, thought he could get away with letting Lehman Brothers, the investment bank, fail; he was wrong. The plight of investors trapped by Lehman’s collapse — as an article in The Times put it, Lehman became “the Roach Motel of Wall Street: They checked in, but they can’t check out” — created …