Brace yourselves, postal patrons!

Here comes the postal union with demands for several stiff rounds of pay raises - raises far above the rate of inflation.If those demands are granted by the Postal Service, which has a record of showing anything but a stiff spine, it's bound to mean not only higher charges for stamps but also higher prices from businesses that rely heavily on the mails.

This situation likely means less patronage for the Postal Service and more patronage for the telephone company and for fax machines.

Logically, it also ought to mean more demands for Congress to deprive the Postal Service of its monopoly on delivering first-class mail and let private firms start competing for this business.

In any case, the demands of the union are simply outrageous: Raises of 8 percent next year, 7 percent in 1992 and another 7 percent in 1993.

These demands can't set well with the public. Postal workers already make an average of $37,048 a year in wages and benefits, well over the $25,223 average for all workers in the private sector. What's more, the Providence Journal reports, the average base salary of postal workers is $2,000 over those of teachers and police officers. At the same time, postal productivity pales in comparison with that of other portions of the communications industry.

Such raises, the Postal Service reports, would likely result in the escalation of the cost of a first-class stamp from the 30 cents scheduled next spring to 43 cents in 1993.

Instead, how about letting private firms deliver more mail, at least on an experimental basis to show what they could do?

The move just might result in better service at lower cost. The former U.S. Council on Wage and Price Stabilization once concluded that "the prod of competition . . . would retard or reverse the upward rush of postal rates" and lead to more prompt and efficient delivery of first-class mail.

Competition keeps prices down and service up in plenty of other enterprises. How much longer must postal costs keep spiraling upward before the same sound principle is extended to the delivery of the mail?