President Bush plans to tell Congress today that he will withdraw his threatened veto of the 1990 Civil Rights Act if lawmakers approve compromise language drafted by the White House, but civil rights leaders yesterday dismissed the language as a "cut-and-paste" collection of previously rejected proposals.

After a frenzied day of negotiations, Sen. James M. Jeffords (Vt.), one of the Republicans leading the effort to avoid a presidential veto, said, "The negotiations fell apart. They {the White House} rejected proposals submitted by the civil rights groups, and they feel no further negotiation would be fruitful."

Ralph Neas, executive director of the Leadership Conference on Civil Rights, said the White House proposals as described to him were unacceptable. He called them a "cut-and-paste collection of proposals" that Congress or civil rights negotiators have already rejected during months of talks. The attempt to produce new language was part of a flurry of last-minute White House and congressional efforts aimed at avoiding a veto of the legislation, which is strongly supported by some moderate Republicans and by the civil rights community. The bill's backers organized a lively demonstration outside the White House yesterday to keep pressure on Bush.

Bush has threatened to veto the bill on grounds that it would force employers to resort to quotas based on sex and race to avoid being sued in discrimination cases. The most contentious issue, and the subject of the attempts to draft new language, centers on one of six Supreme Court decisions last year. Those decisions, taken as a whole, make it more difficult for women and minority workers to win job-discrimination complaints.

In one of those decisions, Wards Cove Packing Co. v. Atonio, the court efffectively set aside an 18-year-old standard that placed the burden of proof on businesses to show that their hiring and promotion practices were based not on discrimination but business necessity. In effect, the new standard requires employees to prove discrimination. The new civil rights act shifts the burden of proof back to business but the definitions of how business would proceed has been the central battleground.

Sources said William T. Coleman Jr., the former transportation secretary who has been trying to broker a compromise between the civil rights community and the White House, proposed new language but that the White House rejected it. Instead, its language in the pivotal segment of the bill is slightly revised from what the White House proposed and the bill's proponents rejected in mid-July.

Neas said the language leaves "a giant loophole" for employers facing discrimination charges by providing a new, weaker standard under which they can defend themselves. Opponents allege the language will do almost exactly the opposite of what the civil rights act intends because it would virtually legalize the Wards Cove case standards that the act is seeking to overturn.

In addition, the White House would significantly reduce the act's $150,000 cap on damages for women and other victims of discrimination who cannot now get such awards, would deny jury trials in those cases and would deny damages if back pay were awarded, according to sources.

The legislation, passed this week by Congress, has not been sent to the White House, and it appeared that its arrival was being deliberately held up while a final effort to reach agreement continued.

Several hundred demonstrators chanting "Sign it, sign it" marched outside White House gates yesterday as press secretary Marlin Fitzwater reiterated that Bush would veto the measure in its present form.

"After months of the most thorough review possible and the most painstaking negotiations, it is clear that this is a quota bill that sets back the course of civil rights," he said. "If it is not changed, it will be vetoed."

Republicans in Congress were split on the legislation in votes this week, and that GOP division was reflected inside the White House, where several of Bush's senior staff, including White House Chief of Staff John H. Sununu, were reportedly in favor of the new search for a compromise but a handful were sharply opposed. White House Counsel C. Boyden Gray, argued that Bush should veto the legislation as soon as it reached the White House, sources said.

The political theater outside the White House contained some harsh references to Bush, who has had cordial relations with the civil rights community until now. Joseph E. Lowery of the Southern Christian Leadership Conference said Bush was "marching to the beat of the Louisiana bayou" in opposing the act, a reference to David Duke (R), the former Ku Klux Klansman who gathered a large white vote in his unsuccessful bid for Senate there and was condemned by GOP officials as a racist.