TEXAS GOV. George W. Bush has taken a version of the unfortunate no-new-taxes pledge that so bedeviled his father as president nine years ago. It may be that the qualified language the younger Bush used leaves him the maneuvering room that his father famously lacked; his supporters have to hope so. Otherwise he could face, if elected, the same unpleasant choice his father did, between breaking his word and losing the ability to govern.

The next president seems fated to face many of the same problems that this one is busily finessing. That's what the finessing is all about. Chief among them likely will be putting the main forms of aid to the elderly and disabled -- Social Security, Medicare and, insofar as it provides long-term care, Medicaid -- on a sound financial footing as the baby boomers prepare to retire. Probably that neither can nor should be done without providing additional revenue atop the benefit and cost constraint that also will be required. Nor may aid to the elderly be the only area in which additional revenue is required. The surpluses thought to lie ahead could disappear as rapidly as they arose a couple of years ago to the great surprise of the same estimators who now suggest they will endure.

Gov. Bush did not say, "Read my lips; no new taxes," as his father incautiously and unnecessarily did -- and later regretted, having been driven by the math of the budget to sign a tax increase. He was more specific, and thereby, more elliptical. As president he would "oppose and veto any increase in individual or corporate marginal income tax rates or individual or corporate income tax hikes," he wrote an anti-tax group on the eve of the opening foray of his campaign. He would also "oppose any further reduction of income tax deductions and credits, unless offset dollar for dollar by reducing tax rates."

In theory, that would leave him free to support other possible tax increases -- in payroll or consumption levies, for example. But one of his objections to an income tax increase is that it would "remove money from the pockets of Americans at a time when taxes already take a record peacetime share of national income." So it isn't clear.

There needs to be an honest discussion of taxes in the coming presidential campaign. As part of that, a candidate would well say, usefully, that he or she would countenance a tax increase only as a last resort, meaning if it was the only alternative to an irresponsible fiscal policy after spending had been so cut that to cut it more would do clear damage.

But the nominating process militates against that kind of nuanced discussion. The pressure instead is to be purer than pure on the short list of symbolic issues, of which this is one, that matter most to the party members most likely to vote. One of the tests of the season, for all the candidates of both parties, will be the extent to which they bow to such pressures or resist.