• Last of a series

The polar extremes of the debate over Social Security are represented by two diametrically opposed notions: (1) The system is in crisis and demands a radical overhaul. (2) It isn't broken, so don't fix it. The case for comprehensive change, particularly ''personal accounts'' and the massive debt this would entail, doesn't stand up to close scrutiny. The case for leaving Social Security alone, however, is not wholly satisfactory either because the projected gap between revenue and benefits would make the system insolvent over the long run.

Social Security has managed to deliver universal and enduring benefits since its inception despite dire threats of long-term insolvency. This can be attributed to wise political leadership capable of ensuring the program's fiscal soundness by undertaking careful planning and modest adjustments.

In the beginning, the payroll tax was set at 2 percent and the initial ceiling was $3,000 of income. In the ensuing 70 years, the ceiling has increased 38 times to the current $90,000, and the payroll tax is 6.2 percent (12.4 percent counting the employer match). In the mid-80s, a commission led by Alan Greenspan, the current chairman of the Federal Reserve Board, hiked the retirement age from 65 to 67. This is still being phased in.

Clearly, preceding generations of Americans have been willing to make a sacrifice in order to keep Social Security going. It's safe to say that they didn't like increased taxes or delayed benefits any more than today's wage-earners do, but they were willing to bite the bullet. The question is whether today's political leaders and the voters they answer to have an equal measure of foresight and will fight to keep the safety net intact for everyone. If the answer is Yes, many options are available:

• Our preferred solution is increasing the ceiling on income subject to payroll taxes. Among other things, it reduces the regressive aspect of the tax. (Only about 6 percent of Americans earn $90,000 or more a year.) Although President Bush has ruled this out, by one estimate raising the ceiling to $200,000 would, by itself, almost eliminate the entire projected deficit. Increasing the level of the tax above 6.2 percent, which would affect all wage-earners, and employers as well, is less palatable.

• Delaying the retirement age. This effective cutback in benefits would reflect longer life expectancies. Coupled with an increase in the income ceiling, the preferred option, this could eliminate the projected gap altogether with only modest changes. A related idea, suggested by Mr. Bush, would discourage early retirements, another money-saving step.

• Reducing benefits for wealthy retirees. This undermines the idea of a ''universal'' benefit and puts the burden for fixing the problem on a relatively small number of the economically active population.

• Altering the way benefits are measured -- a significant change. Instead of indexing the increase in future benefits to preretirement earnings, the index would be tied to inflation -- the increase in consumer prices. This would reduce benefits because wages tend to rise faster than prices. In effect, a worker's standard of living would be locked in at an early stage. Downside: Benefit reductions would be drastic. Upside: It could produce a surplus over 75 years, instead of the projected $3.7 trillion deficit.

The best guarantee of prosperity for all Americans -- including retirees -- is a sound economy. At the moment, a huge deficit and the increasing foreign debt -- billions owed to China and other creditors -- pose bigger threats.

Even more alarming was last week's startling news that the estimated 10-year cost of the Medicare prescription drug program has risen to $724 billion. This for a benefit that didn't even exist in law one year ago.

To borrow a phrase from Thomas Jefferson, this is a fire bell in the night; it makes a mockery of all plans to balance the national budget. If Congress and the president are searching for what's broke and needs fixing, they need look no further than the runaway cost of healthcare. By comparison, Social Security is solid as a rock.