One of the many things Jimmy Carter has learned while managing the world's biggest company is that hell hath no fury like an employee who loses a free parking space.

Since Carter ended most free federal parking last year, the White House has been bombarded with letters, petitions and some threats from irate G-persons. Legal funds have been formed to fight pay parking. The White House has been picketed at least twice, and many feds claim the decision made them born-again Republicans.

Under the president's plan -- designed to encourage car pooling and use of public transportation -- thousands of U.S. workers began paying half the commercial rate (or a minimum of $10) for spaces they once got free. Eventually they are to pay the full commercial cost of parking in their area.

Under the half-free rate, the typical federal parker here now pays about $12 a month in the suburbs, and up to double that downtown.

When pay parking was announced, many long-time Washington watchers said it never would work. Carter may bring peace to the Middle East, solve inflation and teach Americans of all races and creeds to love one another. But they said he could never make pay parking stick in government.

Workers who lost free parking spaces reacted differently. Some simply gnashed their teeth and paid fees under a new bureaucratic structure set up to issue permits, stickers and collect money. Others started parking in residential areas near the office. This has led to continuing guerrilla warfare -- slashed tires, notes on windshields, fist fights -- between home owners guarding their turf from federal interlopers.

Seasoned feds have, as they do best, been working quietly through channels to undermine the program. They are seeking the magic escape hatch of all government orders -- called "The Exemption."

For every federal requirement, there is an exemption. In the case of pay parking, it includes van pools, the handicapped, night workers, and those in locales where public transportation is inadequate. Some would say this takes in all of metro Washington.

Using the lack of adequate public transport as a springboard, a number of federal agencies are winning exemptions from pay parking. Most recently, free parking lots have returned to the big Naval Research Lab and the Defense Mapping Agency. Both are in suburban Maryland.

The exemptions, in the case of the NRL, were granted in part because a nearby federal agency earlier had been given an exemption from paid parking. If they get it, NRL argued, why not us? Now other agencies will argue, if NRL got it, why not us? The possibilities are endless.

Some DMA employees, however, are not content with the return to free parking. There is talk of a lawsuit to get back the $10 a month that several thousand employees paid for parking when it was required. That could cost the government a bundle and it could cost other agencies a shot at free parking if the government believes they, too, will sue to get already-paid parking fees returned.

Maybe the pay parking issue is too much for this president, or any president, to enforce. Maybe the White House should stick to simpler tasks -- like world peace, population control or weather modification -- and leave the real hot potatoes -- like parking spaces -- alone.