NOW THAT the gasoline tax is under semi-serious consideration by the deficit cutters, the familiar objections to it deserve a further answer. It can be summed up in one question: What tax capable of raising enough money do you like better? Our own first choice has always been the income tax -- the fairest of all the federal taxes, intricately designed to take account of each taxpayer's special circumstances. But both President Reagan and Congress are flatly unwilling to raise income taxes. The gasoline tax is the best of the second-best choices.

It's the best because, in addition to raising money simply and cheaply, it encourages drivers to save fuel. With oil imports rising steadily and the war in the Persian Gulf continuing, a higher gasoline tax would serve two purposes. Both have great importance to this country.

The chief defect of the gasoline tax is that it is regressive. It takes a larger percentage of poor people's incomes than rich people's. But that's true of any consumption tax -- the taxes on alcohol, or tobacco, or telephone use, or the national sales tax that seems to be not very far in your future. Except for the income tax, any tax raising enough money to be useful will have to be a broadly based consumption tax. The alcohol and tobacco taxes also serve useful social purposes, but both would have to be doubled to raise as much money, together, as another dime on a gallon of gasoline.

Since the tax is regressive, Congress can relieve the burden on the poor and near-poor by enacting an income-tax deduction for federal gas taxes. In 1979 Congress abolished the deduction for state gas taxes on the excellent ground that it subsidized driving in a time of fuel shortages. But if a new deduction is necessary to get a rational and useful fuel tax increase, then it's a deduction worth passing. The highway lobby, fighting any increase in the gasoline tax, claims that it would cost thousands of jobs. That sort of attack can be made against any tax proposal, since it simply counts the negative effects -- but not the positive ones -- of reduced consumption. How about the job losses that would result from a third worldwide oil crisis?

The price of a gallon of gasoline, adjusted for inflation, currently costs no more than it did at the time of the first oil crisis in 1973. Since the price peaked in early 1981, during the second crisis, it has fallen by nearly half. The time to raise the tax is when the price is low by historical standards and consumption is rising -- that is, now.