Too bad it took massive deficits to do it. But they have opened a window to the basic tax reform that America has long needed. From all accounts President Reagan is going to seize the occasion.
Public pressure can help ensure that neither the White House nor Congress lets the call for reform become a windy substitute for concrete action. Too many windows of opportunity have been allowed to slide shut in the past. Hope for sustained public concern this time lies in the recent urgings by business groups , taxpayer organizations, and a bipartisan array of former cabinet heads.
What should be the elements of tax reform? Mr. Reagan is said to be considering various options this weekend in preparation for his State of the Union message. At least two new/old thrusts can hardly be ignored:
* Making taxes simpler and fairer. The revival of congressional interest in the ''flat tax'' - one low rate for all and no deductions - dramatizes the harried tax reckoner's yearning for simplicity. The questioning of this tax's greater advantages for high-income people reflects the public's concern for fairness also.
The answer could lie in a flat tax with a substantial income exemption. This would provide relief for low-income people. And it would retain something of America's now legally prescribed ''progressive'' taxation. For example, an exemption of $20,000 would offset 100 percent of the income of a family at the $ 20,000 level but only 50 percent at $40,000 and 10 percent at $200,000.
Another possibility would be a tax not wholly flat but with perhaps four progressive tax rates. Instead of eliminating all deductions it might allow such widely favored ones as interest on home mortgages and contributions to charity.
With or without a flat tax, the cause of simplicity and fairness could be served by one long-advocated reform: pruning the deductions, credits, subsidies, and loopholes that create both complexity and unfairness.
* Taxing consumption more and savings less. One anomaly of the present system is evident. People who pay interest on consumer expenditures can deduct it; people who receive interest on saved or invested money cannot deduct it. Thus there appears to be more tax incentive to borrow than to save at a time when government deficits call for a larger savings pool.
A complication at the moment is that the economy also requires people to spend more if growth is to be achieved and jobs restored. The argument for more consumption taxes would be to obtain such results by improving the whole economy. How? By reducing deficits while continuing to encourage investment, saving, and income-producing initiative. The snag is unfairness: Sales or other consumption taxes hurt low-income people proportionately more than high-income people.
So the most careful scrutiny would have to be given to a return of the idea of an overall tax on expenditures rather than receipts - one of the approaches floated by the White House this week. Parts could be considered separately, such as fully taxing capital gains that are spent on consumption and not taxing such gains at all if reinvested.
Similarly the new discussion of the VAT (value added tax), long established in Europe, should include specifics. This is a tax paid at each stage of a product's making and marketing by manufacturers, distributors, and ultimately consumers. In fairness to low-income taxpayers, as noted in bygone congressional proposals, exemptions for food, clothing, and other necessities should be considered as part of any VAT. How would these affect simplicity and revenue?
The details are important. But they are just as difficult when tinkering with an outmoded tax system as when planning a reformed one. Why not go for the latter while the window is open?