House Democrats, flexing their majority muscle on the first day of the 102nd Congress, yesterday rammed through a rules change that undercuts a key procedural provision of last year's budget agreement with the Bush administration.

Over the strenuous objections of Republicans who charged they were reneging on the budget deal, Democrats won House approval of the change on a 242 to 160 party-line vote.

The provision, part of a package of mostly minor rules changes adopted yesterday, would strip from the White House's Office of Management and Budget (OMB) the power to determine whether certain spending and tax measures violate spending targets set by the budget pact. Under the new rule, that estimating power is effectively given to the Congressional Budget Office (CBO) and Congress's Joint Committee on Taxation.

Although the provision may seem relatively obscure to those outside the federal budget process, the so-called "score-keeping" authority is a key factor in determining whether tax cuts or new spending programs will result in automatic spending reductions to make up for such added costs.

Under the five-year budget agreement, any tax cuts or new spending on entitlement programs such as Medicare must be offset by either higher revenues or reduced spending elsewhere in the federal budget. If they are not, automatic spending cuts take effect.

The House Democrats' action drew an immediate and angry response from President Bush and White House Chief of Staff John H. Sununu.

Bush said changing the rules on a partisan vote was "neither fair nor right" and "puts into serious doubt whatever they might say or promise the American people on other significant issues in the upcoming session."

Under the rules change, any legislation affecting spending must incorporate as part of its text a CBO cost estimate for purposes of the "pay-as-you-go" requirement of the budget deal. Tax legislation would have to contain similar estimates by the Joint Committee on Taxation.

Bush yesterday reiterated a threat to veto any legislation that contains such language. In letters to House members sent on Wednesday, Bush said that "the rule change will undercut the credibility of the entire budget agreement. The provision was specifically negotiated and agreed to and, if there is to be any credibility to such processes, cannot be arbitrarily reversed."

"It's insane," Sununu exclaimed to a visitor after watching the House vote. "It is a clear violation of the {budget} agreement and of the bill Congress passed and the president signed into law."

Sununu, who was one of the principal administration negotiators in last year's marathon budget sessions, said the "arrogance" and "abuse of trust" by the Democrats in the opening hours of the new Congress sent a signal of partisanship that the White House could not ignore.

"This is the kind of behavior that calls for an overhaul of Congress," he said.

Led by House Minority Leader Robert H. Michel (R-Ill.), Republicans sought unsuccessfully yesterday to thwart the change and simultaneously set a date for House consideration of a constitutional amendment requiring a balanced federal budget. Despite the link to a balanced-budget vote that is supported by many Democrats, the House defeated Michel's proposal on a party-line roll call. "An agreement is an agreement," said Michel, who charged the Democratic leadership with "defaulting" on its part in the deficit-reduction deal.

"The budget deal was supposed to last for five years," added Minority Whip Newt Gingrich (R-Ga.). "It's being broken on the first day Congress is sworn in."

But Democrats, who deeply distrust the OMB and frequently charge it with politicizing its fiscal estimates, defended the change. House Ways and Means Committee Chairman Dan Rostenkowski (D-Ill.) said that Republicans should have no fear of giving the score-keeping power to the CBO because that nonpartisan congressional agency is "independent and objective."

Staff writer David S. Broder contributed to this report.