D.C. Vote Advocates Jack Up Pressure

"The Republicans don't want to allow anything to get out of the Senate," Manley said, noting the minority party's frequent objections to legislation this year.

Don Stewart, a spokesman for the Republican leader, pointed out that some bipartisan bills had cleared the Senate. But "unconstitutional legislation, the senator has no interest in moving," he said, referring to the D.C. vote bill. No decision has been made yet on a filibuster, he added.

Zherka said supporters of the measure were "pretty comfortable" they would get the votes of at least four senators in addition to the 51 already committed.

"The question for us is, where do seven to 10 additional senators stand? That's where a lot of the work is being done right now," he said. He declined to list them all.

But he and other advocates acknowledge they are hoping to pick up votes from such moderate Republicans as Olympia J. Snowe (Maine), Gordon Smith (Ore.) and Arlen Specter (Pa.). Another possible ally is Sam Brownback (R-Kan.), a leading member of the subcommittee overseeing District affairs, advocates say.

Two senators who sponsored the bill, Hatch and Joseph I. Lieberman (I-Conn.), dispatched a letter to their colleagues last week urging them to support it. A similar letter was sent to senators by the Federal City Council, an influential group of business and civic leaders headed by Frank Keating, the former Republican governor of Oklahoma.

Mayor Adrian M. Fenty (D) has also been campaigning for the bill, focusing on a small group of senators including Specter, Brownback and James Webb (D-Va.). Webb is planning to vote for the legislation, said his spokeswoman, Jessica Smith.

The mayor is "making phone calls, knocking on doors of senators, and he'll be doing more of that in the coming weeks," said Neil Richardson, a top aide.

Supporters of the bill aren't just talking to senators who might support it. They're also trying to persuade opponents to support an up-or-down vote on the legislation.

"What we're saying is . . . if you're not going to vote for it, don't filibuster," Rep. Thomas M. Davis III (R-Va.) said. He and Eleanor Holmes Norton (D), the District's nonvoting delegate, sponsored the D.C. vote bill that passed the House in April.

One powerful senator, John W. Warner (R-Va.), has said he will vote against the bill but might not back a filibuster.

Proponents of the legislation are hoping for a floor vote in July. But other priorities on the Senate calendar include a children's health insurance bill, defense authorization legislation and other spending bills. The Senate is scheduled to take off next week and begin a month-long recess in early August.

President Bush's advisers are urging him to veto the bill if it passes the Senate, according to a White House statement. Their objections are constitutional: Membership in the House is limited to states, they note, and the District is not a state. Supporters of the legislation say the Constitution gives Congress enough power over the District to give it a House seat.

So far, there is little sign of White House pressure on senators, according to Senate aides from both parties and advocacy groups. That could change, though, if a floor vote draws near.

Some of the bill's supporters are trying to portray a filibuster as a potential public-relations disaster for Republicans, noting that the tactic was famously used by Southern senators trying to block civil rights legislation.

"That's a dark part of our history," Zherka said.

Staff writer Yolanda Woodlee contributed to this report.