A report that the federal government has stepped in to rescue Citigroup with a $20 billion “investment” — the latest in a string of such investments that will cost taxpayers more than more than $4 trillion — turned out to be good news for the battered stock market, which closed Monday with its biggest two-day percentage gain since in the 20 years since the historic Black Monday crash.

Obviously, investors are pleased at the government’s promise to guarantee some $306 billion in risky loans. Many of us, however, are a bit less enthusiastic about the pace at which current and future Americans are being committed to paying for the profligacy of the financial industry.

Amidst all of this generosity toward reckless lenders, Big Automotive has stepped into the fray, hat in hand, hoping to catch a few of the billion-dollar bills that Uncle Sam might drop while he’s got his wallet out. Congress has made a show of resistance, but it won’t last. Detroit’s favorite uncle is sure to come through once more.

It’s a perfect irony.

When the guy selling buggy whips down the street goes out of business because he didn’t anticipate the effect on his business of changing market conditions, he becomes a clichéd cautionary tale for young business students. But when the giant automotive company whose product put paid to the buggy whip now finds itself in a similar predicament for similar reasons of corporate myopia, government steps in to help.

It’s just one more example of a unique feature of the American blend of politics and capitalism: Fail small, and you fail on your own. Fail big, and you never know who’ll come to the rescue.