Sen. Wendell H. Ford (D-Ky.) had reason to revolt. Senate leaders were pushing through the chamber a tax-overhaul bill that would repeal deductions for state and local sales taxes -- a change that stood to hurt Ford's Bluegrass State more than most.

The wily Kentuckian got his chance to stand up for his constituents Thursday when an amendment was offered to restore the sales tax writeoff.

But the amendment had a price: It saved one deduction, and in exchange traded away a tax break the bill would give homeowners. When Ford stood up for Kentucky, it was to announce that the price was too high for his constituents.

"This may be a good amendment," Ford said, "but you have gone at it wrong. You are knocking down the root of the family by saying they cannot use their No. 1 asset. So you have made the No. 1 mistake . . . . You have gone after my castle, the only thing I have."

The amendment was defeated, 51 to 48.

Ford's tradeoff -- sacrificing one cherished tax break to protect another -- is part of a quiet revolution that tax overhaul has brought to the Senate. For the first time in recent history, a major tax bill is steaming toward Senate passage almost unamended. The Senate resumes action on the measure today and is expected to pass it by Tuesday or Wednesday.

"Not long ago," recalled Sen. John H. Chafee (R-R.I.), "amendments were added willy-nilly. What restraint was there? Let the state of Washington deduct sales taxes! Let someone else have their Individual Retirement Accounts! IRAs are wonderful, let's have IRAs! That's how it worked."

The revolution grows from an unusual combination of circumstances: a tax bill promising rates so low that it appears to have caught public imagination, a spirit of austerity dictated by the federal budget deficit and a political idea on which Washington's often-warring camps of Congress, the White House, Democrats and Republicans are amazingly in sync.

The bill would eliminate a wide range of tax breaks in exchange for slashing tax rates -- from a maximum of 50 percent to 27 percent for individuals and from 46 percent to 33 percent for corporations. It would remove roughly 6 million low-income Americans from the tax rolls, abolish most tax shelters and generally "level the playing field" on which businesses compete.

One key force behind the change in the Senate is the Gramm-Rudman-Hollings deficit-reduction act, whose passage made it an article of faith that Congress would not take action that increases the federal deficit. Gramm-Rudman-Hollings has turned fiscal politics into a zero-sum game, observed Thomas Mann, executive director of the American Political Science Association and a specialist on Congress.

If Sens. Daniel J. Evans (R-Wash.) and Phil Gramm (R-Tex.) wanted their constituents to be able to deduct state and local sales taxes, as they proposed Thursday night, they either had to raise tax rates, a political taboo, or take it from something else -- in this case, from Ford's house.

Similarly, Sens. Alfonse M. D'Amato (R-N.Y.) and Christopher J. Dodd (D-Conn.) tried to save full IRA tax benefits by hiking taxes on corporations and wealthy individuals, which on the surface seemed a tempting pair of targets.

But the proposal was shown to hit natural resource industries particularly hard, and the combination proved fatal: timber, oil and mining state senators coalesced with other opponents to kill the amendment.

Next up was Sen. Max Baucus (D-Mont.) with another plan to save IRAs, this one proposing to pay the freight by trimming everyone's itemized deductions by $310 -- a proposal that hit constituents of every senator. The backlash was even stronger. Baucus lost, 76 to 21.

"We decided IRAs were wonderful, but we weren't willing to belly up to the bar to pay for them," Gramm said.

"You get a double whammy with every amendment," said Sen. Alan Cranston (D-Calif.), among those voting unsuccessfully to save current IRA deductions. "You get attacked for whatever you're doing to change a popular tax bill, and then you come up with an extraneous way to pay for it -- and they attack you for that."

The dynamic likely would have brought smiles to the faces of the Founding Fathers if only they could have foreseen it -- special interests canceling each other out, much as James Madison envisioned the government working in the Federalist Papers: "Ambition must be made to counteract ambition."

"Madison wanted to pit faction against faction, out of which emerged the general interest," said Sen. Bill Bradley (D-N.J.), a founding father of tax overhaul. "Our approach was to start out asserting the general interest -- lower tax rates -- and now you have fratricide when somebody tries to change it."

This is not to say that the Senate has gone Puritan. Within the bold outlines of the tax bill, passed unanimously by the Finance Committee last month, are protections for interests ranging from oil to defense contractors to high tech to employer-provided health insurance.

Many of these exceptions help the committee members' home states, and probably would not have been able to survive a floor vote. Referring to the defense contractors' break, advocated in the committee by Sen. John C. Danforth (R-Mo.), Chafee said: "That shows the value to St. Louis home of McDonnell Douglas Corp. of having Jack Danforth on the Finance Committee."

Efforts to repeal these exceptions generally have met the same fate on the Senate floor as efforts to open new loopholes.

For example, Sen. Lowell P. Weicker Jr. (R-Conn.) sought in vain to remove from the bill's overall crackdown on tax shelters an exception for certain oil and gas deals -- included at the behest of committee members Robert J. Dole (R-Kan.), Russell B. Long (D-La.), David L. Boren (D-Okla.), Lloyd Bentsen (D-Tex.) and others. Weicker argued that this provision violated the bill's overall spirit of fairness.

But he lost, 77 to 20, abandoned by longtime oil-industry skeptics such as Chafee, Edward M. Kennedy (D-Mass.) and New Jersey's Bradley.

The reasoning, as the three later said, was that the success of any one amendment -- even one they believed in -- could open the floodgates. Since advocates of IRAs had helped vote down the IRA amendment and senators from states with high sales taxes had held the line on their pet issue, they were bound to cast their lot with oil.

"I suspect I am going to get rolled on this amendment," Weicker said accurately just before the vote on his oil proposal. "By the time you are through with those who want to see a tax bill pass and those who come from the oil-and-gas-producing states, all of a sudden the issue of fairness, which is most dear to the little man, gets lost . . . . How refreshing it would be to see something clear this place that did it on its own merits."

Another reason for the unusual unity was the cost of breaking ranks. That became evident soon after Sen. Pete Wilson (R-Calif.) broke with the leadership to support the Dodd-D'Amato IRA amendment, which was narrowly defeated.

When Sen. Howard M. Metzenbaum (D-Ohio) later moved to eliminate a special break exempting a key constituent of Wilson's -- Unocal Corp. of California -- from large, existing tax liabilities, Finance Committee Chairman Bob Packwood (R-Ore.) stepped aside and freed his troops to repeal what Metzenbaum called a "fresh-off-the-shelf loophole." Packwood voted with Metzenbaum.

That was the only change allowed in the bill so far.

"For every temptation that comes along," Packwood said at week's end, "So far we have stood together."

Staff writer Anne Swardson contributed to this report.