WHO shot General Motors? The company’s stock is at its lowest level in 50 years, and its market valuation has plunged to $5.9 billion, less than that of the Hershey candy-bar company. The automaker is weighing yet another round of layoffs  and maybe even a fire sale of venerable brands like Buick and Pontiac.

General Motors once manufactured half the cars on the American road, but now it sells barely 2 in 10. Bankruptcy is not unthinkable for Detroit’s former king. The immediate cause of G.M.’s distress, of course, is the surging price of oil, which has put a chill on the sale of gas-guzzling sport utility vehicles and trucks. The company’s failure to invest early enough in hybrids is another culprit. Years of poor car design is another.

But none of G.M.’s management miscues was so damaging to its long-term fate as the rich pensions and health care that robbed General Motors of its financial flexibility and, ultimately, of its cash.

General Motors established its pension in the “treaty of Detroit,” the five-year contract that it signed with the United Automobile Workers in 1950 that also provided health insurance and other benefits for the company’s workers. Walter Reuther, the union’s captain, would have preferred that the government provide pensions and health care to all citizens. He urged the automakers to “go down to Washington and fight with us” for federal benefits.