Senate Democrats on Friday abandoned their demands that first-time voters be allowed to prove their identity with merely a signature, a major sticking point in the debate over overhauling elections.

The agreement removed the biggest hurdle to passing a $3.4 billion bill aimed at preventing a repeat of the 2000 Florida presidential vote dispute. The House passed its $2.6 billion version in December.

But another dispute — over Democratic demands to exclude Oregon and Washington state, both of which have vote-by-mail systems — remained a stumbling block.

Senate Majority Leader Tom Daschle, D-S.D., said lawmakers have until Tuesday to reach a compromise.

If they don't, "I will just assume Republicans have killed the bill for good," Daschle said Friday.

Democratic Sen. Chris Dodd of Connecticut, the measure's author, said he was confident a deal would be reached.

"There's been concern this bill might die," Dodd said. "That's not going to happen. This bill is going to be resolved by Monday night or Tuesday morning."

Republican Sen. Kit Bond of Missouri agreed. "We are moving toward agreement," he said.

Early Friday, Democrats failed to get the 60 votes needed to end delaying tactics and draw the lengthy debate to a close.

Republicans want first-time voters who register by mail to present photo identification or proof of address, such as utility bills, bank statements, paychecks or government-issued documentation when they show up to vote.

Democrats had pushed to allow those voters to guarantee their identities by signature, matched by records on file with state or local election officials.

As part of the compromise being discussed, the identification provisions remain but won't kick in until 2004. That's when the bill also begins allowing provisional voting. Under provisional voting, people who do not appear on election rolls but say they are eligible to vote could vote. Election officials later would determine whether the ballots were valid.

The compromise also includes money so that jurisdictions could get voter identification cards for people who lack the documents allowed under the bill.

"We're willing to walk in their direction to get a bill," said Sen. Charles Schumer of New York, one of the Democrats who had pushed for the signature provision.

The identification provisions, if they remain, are certain to draw the ire of civil rights groups, who have complained that poor people and minorities will be disproportionately affected.

The measure is the Senate's response to balloting problems that emerged in the last presidential election. It includes accessibility provisions for the disabled and computerized state registration lists. Once the Senate completes its bill, it'll be up to House and Senate negotiators to reach a compromise.