The past week, by any standard, has been an extraordinary one for America’s economy and its financial system. Merrill Lynch, which was founded during Woodrow Wilson’s administration, agreed to be bought for a bargain-basement price, while Lehman Brothers, which dates back to John Tyler’s presidency, simply collapsed.

By the end of the week, the federal government was preparing to buy hundreds of billions of dollars in securities that no bank wanted. It appears to be the government’s biggest fiscal intervention since the Great Depression, designed to get the financial markets working again and keep a credit freeze from sending the economy into a deep recession.

The announcement of the plan changed the mood on Wall Street and sent stocks soaring at the end of the week. But even if the economy avoids a tailspin, the next couple of years aren’t likely to feel especially good. It’s been a long period of excess, and the hangover could be long, as well. For the near future, the most likely outcome remains slow economic growth, scant income gains for most workers and, for investors, disappointing returns from stocks and real estate. If consumers begin to cut back on their debt-fueled spending things could get worse.

On Friday morning, the economists at Lehman Brothers sent out their usual weekly roundup of the news, but it came this time with a short, italicized note, explaining that the report would be the final one to appear under the Lehman banner. That bit of understatement preceded some more: “This episode of financial crisis,” Lehman’s economists explained, “appears to be much deeper and more serious than we and most observers thought it likely to be. And it is by no means clear that it is over.”