Tax candor

Amid the current brouhaha between Walter Mondale and President Reagan over whether or not taxes will have to be raised next year as part of a larger federal budget deficit-reduction plan, it is important to recollect a basic fact about American presidential campaigns in general:

Like it or not, political campaigns in the United States tend to be played out on their own internal sense of ''reality,'' which may, or may not, have any actual resemblance to the practical world of government. In 1932, Franklin Roosevelt in part ran as a fiscal conservative, who would trim profligate government spending and rein in the growing federal work force. In 1960 John Kennedy ran against a missile gap that was later conceded not to exist. And on the state level, Ronald Reagan as governor of California promised voters not to raise taxes by increasing withholding. His feet, he said, were cast in concrete on that issue. Later, when signing tax-hike legislation, he wryly commented to reporters that the sound they were hearing was that of ''concrete breaking up around my feet.''

To note all this is not to suggest that American political leaders are necessarily duplicitous - or even ingenuous.

Rather, it is to underscore the fact that government leaders must make decisions based on conditions as they exist at the moment, when action is necessary, and not just on election promises or personal preferences.

It seems safe to assume that Mr. Reagan, a conservative, is instinctively opposed to any increase in personal income tax rates. He has long been a critic of the progressive-income-tax structure. Thus, Reagan's avowals that he has no plans for an increase next year. And, of course, Mr. Mondale, coming from a more liberal political tradition, would probably feel more comfortable going the tax-hike route, if necessary, or cutting defense spending, than having to slash spending for social legislation as a way of reducing deficits. Thus, Mondale's pledge to raise taxes next year.

But that's not the point. The actual economic circumstances to be found next year will largely determine what happens regarding taxes.

As analysis released recently by the Congressional Budget Office suggests, federal budget deficits for the next year or so will be less than were expected earlier, because of the strong growth of the economy and thanks to the recently passed measure raising taxes.

That is, the size of the deficits will probably not be such as to endanger recovery directly, either this year or next.

But what is worrisome in the CBO's analysis is that the deficits swell down the road, in the late 1980s, and - because government borrowing needs may collide with private credit demands - the credit competition could drive up interest rates and work against recovery.

That is why, based on economic conditions as they exist, it seems only prudent that lawmakers fashion a budget-reduction package of some type that includes tax increases. As we have said on this page before, it is absolutely imperative that federal deficits be reduced.

But what happens if the economy dips next year - perhaps not even as a result of conditions within the United States, but because of conditions elsewhere, such as a slowdown in world trade, or a default by a major third-world debtor nation? What if - and this question is only raised in a hypothetical sense - what if the nation even faced recession? Would a tax increase then be good economics, or even politically practical?

The answer, of course, is that it would not be, certainly not for an extensive tax increase of some type. So, as Treasury Secretary Donald Regan and Vice-President George Bush have not unrealistically argued, a president, any president, needs to keep options open on an issue so important as taxes.

A final point: Congress will most likely be even more politically centrist next year than this year. Deliberation on the tax-increase measure just signed into law by President Reagan began - are you ready for this? - in February of last year. It took about a year and a half to get the measure enacted into law. So even if lawmakers take up a revenue measure next year, the likelihood is considerable that it will not make it into law until 1986. That is particularly true if the tax package in any way deals with existing deductions or tax exemptions, each of which has powerful constituencies supporting them.