Congress is about to demonstrate whether or not it is willing and able to put the long-range public interest ahead of short-sighted political expediency.

The test will come early this week when the lawmakers try to override President Reagan's veto Wednesday of the protectionist new textile bill.The bill, which would limit the growth of textile and apparel imports to one percent a year and freeze shoe imports at 1987 levels, is ostensibly aimed at protecting American jobs. Actually, it's aimed at embarrassing the administration just before the elections.

Though some jobs have been lost in the textile industry, imports are not to blame. Instead, the cause is the modernization and consolidation of plants brought on by increased productivity.

Already protected by 1,500 trade quotas, the textile industry doesn't need still more of them. By further restricting imports, the vetoed bill would increase clothing costs to Americans by an average of $250 a year. It also would invite foreign retaliation against imports of American products.

The hypocrisy of the bill can be seen from a provision that would let foreign nations sell more than their quota of textile products in the U.S. if they purchase larger quantities of American farm products. How can that help the textile industry?

If Congress won't sustain the veto of the textile bill, voters shouldn't sustain the lawmakers who work to override the veto.