Corporate pensions have already become an endangered species. Many firms prefer to let their employees make their own retirement arrangements, with combinations of IRAs and 401(k) plans.

Now a new threat has appeared on the scene. A company goes into bankruptcy and tries to persuade the judge that it can no longer survive if it keeps up its expensive pension plan. Dumping a pension plan can almost magically fix a troubled bottom line and may convert a dying corporation into a healthy money maker.

A recent New York Times article headlined “Whoops! There Goes Another Pension Plan” gives startling examples of how this works. The writer, Mary Williams Walsh, focuses on Robert S. Miller, “a turnaround artist with a Dickensian twist” who “unlocks hidden value in floundering Rust Belt companies by jettisoning their pension plans.” Executives of airlines and other troubled companies have copied his maneuver.

She reports that Mr. Miller, as CEO of Bethlehem Steel in 2002, shut down its pension plan with its $3.7 billion unfunded obligations to retirees. With that huge liability off its books, Bethlehem suddenly became an attractive takeover target. A venture capitalist snapped it up, along with other dying steel companies, for a mere $400 million.

Mr. Miller did a similar deal two years later as chief executive of Federal Mogul, a Michigan auto parts maker, trying to end a pension plan for 37,000 employees in England. This time, the British authorities balked, and the deal was delayed. He now is at Delphi, another auto parts maker, and apparently plans to drop its pension plan, underfunded by $5 billion.

The article reports that similar pension dumping has taken place in recent years at Polaroid, Cone Mills, WestPoint Stevens and many smaller companies, in what has become a bailout system relying on bankruptcy laws and the federal government’s pension insurance system.

This can be tough in two ways, The government’s insurance system, the Pension Benefit Guaranty Corp., is already in trouble. Last year, it reported $39 billion in assets and $62.3 billion in liabilities, leaving a gap of $23.3 billion. The Congressional Budget Office has estimated that the deficit will increase to $86.7 billion by 2015 and $141.9 billion by 2025. Taxpayers ultimately must bear the burden.

Retirees suffer, too. There is a cap on the agency’s responsibility for any one pension. And its payments are only a percentage of the originally promised pension.

The system, enacted in 1974, was flawed from the start. Its premiums at first were a flat $1 a head, since increased to a present $19. Far from raising rates high enough to cover its liabilities, the agency has sometimes waived its rules.

A possible solution would be enactment of a risk-based pension insurance system, with higher premiums for poorly run pension funds rated as prone to failure. But some countries have threatened to stop offering pensions if they had to pay more for their pension insurance.

So the outlook is bleak for a system that once allowed a retiree to look

forward with confidence to agreed lifetime pension payments.