If there is anything this nation does not need, it is another hike in the inflation-inducing federal tax on gasoline. Yet here Congress is considering a new five-cent increase in the gas tax on top of the five-cent hike imposed only six months ago.

Up to a point, a persuasive case can be made for the higher tax. It might prompt motorists to drive less and conserve more fuel. Moreover, the need to repair America's crumbling roads and bridges is beyond doubt.About 60 per cent of the nation's 2.1 million miles of paved highway need some form of rehabilitation. In addition, 242,000 bridges - more than 42 per cent of the total - are substandard. The results of this deterioration include more accidents, more fuel consumption, more travel delays, and more air pollution than are really necessary.

But it would be unconscionable for Washington to dip into motorists' pockets to get another $6.6 billion a year when the government is sitting on a $15 billion surplus in the Highway Trust Fund just to make the federal deficit look smaller than it really is.

Besides, the more Washington increases the gas tax, the more it increases the prices of goods and services that must be transported over this nation's highways.

If all that isn't bad enough, consider the short-sighted games that Washington insists on playing with revenue from the gas tax. Since the tax is paid by highway users, it has long been recognized that revenue from the gas tax ought to be earmarked strictly for highway improvements.

But that sound principle has been eroding lately. Only half of last year's hike in the gas tax went for highways; the rest was shunted aside to reduce the federal deficit. As for the proposed new hike, some powerful lawmakers want the money to pay for various other programs, with not a cent to repair roads and bridges.

What folly! Congressmen who come rattling the cup for still another gas tax hike should be told by motorists that we all gave at the office last year.