When Senate Minority Leader Tom Daschle reached back a generation and revived the term "credibility gap" for a rhetorical attack on the policies of President Bush, it was not a casual or accidental choice of words.

Daschle, who was in the Air Force during the Vietnam War, is just old enough to remember how that phrase haunted Lyndon Johnson and the Democrats at the time. It was invented by Murrey Marder, then a diplomatic correspondent for The Post, to describe the gulf between the Johnson administration's upbeat appraisals of the war in Vietnam and the much bleaker (and more realistic) picture being drawn by reporters and other independent observers on the scene.

Johnson, who had been elected in a landslide in 1964, saw public confidence in his veracity -- and, therefore, his leadership -- erode to the point that he decided not to seek reelection in 1968.

So Daschle knew exactly what he was doing when he told a National Press Club audience the day before Bush's State of the Union address: "History is full of politicians whose rhetoric is out of step with reality, who promise something and then fail to deliver. But the Bush administration offers a credibility gap with a new twist. This is a White House that promises one thing knowing full well it is delivering another."

Are the Democrats out of line in reviving these historically freighted words and applying them to another president? They cannot base that claim on Bush's record in international affairs. He has been steadfast in pursuing the war on terrorism -- even if he exaggerates when he says, "We have the terrorists on the run." And with last week's compelling presentation by Secretary of State Colin Powell at the United Nations, Bush has gained support at home and abroad for his showdown with Saddam Hussein.

It is in the domestic arena that his critics find it hard to square Bush's words with his actions. House Minority Leader Nancy Pelosi, sharing the Press Club platform with Daschle on Jan. 27, said that when Bush freezes funds Congress appropriated for homeland defense "but says there is enough money in the wartime budget to create a huge tax cut that benefits the wealthiest in our country, the credibility gap widens."

The budget that Bush delivered last week provides the strongest evidence to support the Democratic charge. The same president who promised in the State of the Union address that "we will not deny, we will not ignore, we will not pass along our problems to other Congresses, to other presidents and to other generations" is burdening the future irresponsibly with debts he will not pay.

The budget message disclosed that in the next two years alone, this administration will pass on to the next generation an unpaid bill of at least $611 billion in fresh budget deficits. The five-year total, by the White House's own estimate, will be more than double that record amount.

Meanwhile, the president omits any provision for financing a possible war with Iraq. And he refuses to face up to the costs of retirement and health care benefits for the baby boom generation, which will drain Social Security and Medicare coffers in coming years.

When John Snow, the new Treasury secretary, came before the Senate Finance Committee last week, he parroted the administration line that -- measured as a percentage of the gross domestic product -- the deficits are "within acceptable range" and smaller than some in the past. But Democratic Sen. John Breaux and Republican Sen. Olympia Snowe, leaders of the centrist bloc on the committee, expressed their incredulity that such mathematical rationalizations would be used to cloud the reality of the rapidly approaching fiscal crisis.

Instead of facing up to that challenge, Bush has continued the parade of tax cuts targeted to top-bracket Americans. Not content with the dividend tax exclusion that he made the centerpiece of his "economic recovery" plan, Bush had the Treasury float a proposal for a new array of tax-sheltered savings accounts that would remove billions of dollars of investment income annually from the reach of the Internal Revenue Service. Were it to become law, the burden of financing government would fall even more heavily on those who depend on wages for their living.

But this last proposal was too much even for some Republicans. The first Ways and Means Committee member approached by the White House to sponsor the scheme flatly refused, and a senior House GOP member with close White House ties told me the package was "a mistake" and would soon be abandoned. But not before it becomes one more entry in the Democrats' "credibility gap" exhibition.