The proportion of the private-sector workforce enrolled in pension plans that pay monthly benefits for life has been cut in half in the last quarter century. In 1980, 39 percent of private-sector workers had a “defined-benefit” pension plan, according to the Employee Benefit Research Institute. In 2004, that number was 18 percent.

Today, when companies offer any retirement benefits at all, the favorite method is a “defined-contribution” plan, like 401(k) plans. The eventual amount of retirement checks is “defined” by contributions to individual accounts by employers and employees.

But unlike pensions, “defined-contribution” plans aren’t guaranteed by the government--and can disappear altogether, as employees of Enron, WorldCom and other companies found out when they lost their retirement savings amid the wave of corporate scandals.

Even when the company survives, 401(k) programs fall short of meeting retirees’ needs. With two-thirds of companies that offer retirement plans using the 401(k) system, retirees will be squeezed by falling Social Security benefits and too little in their private retirement accounts.

“Most people are going to arrive at retirement and not have adequate money,” Alicia Munnell, director of the Center for Retirement Research, told the Christian Science Monitor. Munnell estimates that under the 401(k) system, the bottom one-third of new pensioners will fall into poverty, more than three times higher than the current poverty rate for retirees.

In addition to the turn to 401(k) plans, Corporate America is out to gut the existing pension system.

Airlines, steel and auto are the best-known cases. United Airlines, for example, last year got a bankruptcy judge to approve its decision to default on its pension obligations and dump them into the federal government’s Pension Benefit Guarantee Corporation--which is already responsible for pensions at former giants Pan Am, TWA and US Airways.

Even profitable companies with fully funded pensions are cutting back. For example, IBM announced in early January that it would freeze its pension plan in 2008, and convert to a 401(k)-type defined-contribution system. A similar attempt in the 1990s provoked a class-action lawsuit by IBM employees that proved, according to a federal judge’s ruling, the company was discriminating against older workers by eliminating the defined-benefit formula.

Currently, IBM’s pension system, with $48 billion in assets, is fully funded--the company didn’t even have to make a pension fund contribution in the fourth quarter of last year. But management is determined to be on the pension-slashing bandwagon--to “remain competitive,” said a company official.

The mainstream media have been filled with warnings about an impending pension crisis. The estimated shortfall between the size of pension funds and future obligations to retirees is $450 billion in the private sector, plus another $300 billion in the public sector.

The gap is so big because employers have increasingly found ways to shortchange pension funds. In particular, state governments suffering through years of budget shortfalls are putting off pension contributions to pay for more pressing needs. In Illinois, for example, the pension system for public educators has less than half of what it needs to cover retired and working teachers, yet the state government won’t make annual pension payments in 2006 and 2007.

Nevertheless, the media talk about a pension crisis is misleading. The shortfall would only have any meaning if all pension obligations, to past and present workers, were due immediately.

Pension funds go up and down with the overall economy, and the level of financial markets where pension fund money is invested. What matters is whether benefits can be paid over a period of decades, not the fund level in a particular year.

In fact, during the economic boom of the 1990s, as the stock market kept climbing to new heights, many corporations decided that their pensions were “overfunded”--in other words, the financial assets of the pension funds were worth more than total obligations. Rather than grant more generous benefits, Corporate America skimmed off the surplus as profit.

Now, though, with the stock market fallen back from its peak, companies are using red ink in their pension funds to justify reducing or eliminating benefits.

The financial press today talks about pensions as if they were a “gold-plated” gift to employees. Workers with a decent pension plan--especially those who fight to defend them, like the New York City transit workers--are portrayed as clinging to an fancy perk, at the expense of other working people.

But, of course, neither New York’s billionaire Mayor Michael Bloomberg, nor Gov. George Pataki, nor New York Post publisher Rupert Murdoch will ever worry about what they will live on during retirement.

And seniors living on a pension check don’t live in luxury. Average annual benefits for retired state and local workers were $19,875 in 2004, according to the U.S. Census Bureau. That’s not far from the poverty line for a couple. And because private employers have made harsher cuts, these are the most generous pensions today.

Pensions are another front in the employers’ offensive--with the tiny bunch of super-rich fat cats demanding that working people tighten their belts even more.