Saying she and her allies have nearly enough votes to ward off a filibuster, Del. Eleanor Holmes Norton (D-D.C.) sent Senate Majority Leader Harry Reid (D-Nev.) a letter on Friday urging him to schedule a floor vote on the District of Columbia House Voting Rights Act before the August recess.

Although the Senate still must take up all of the appropriations bills and a range of other measures this year, Norton told Reid the D.C. bill must be a priority because July probably will offer the best chance for passage.

“We already have a healthy majority for passage, and we are very close to getting the necessary votes for cloture should that prove necessary,” Norton wrote. “We are especially encouraged by the number of senators who say that at the very least, they will vote for cloture.”

At a meeting last month with Norton and other D.C. officials, Reid promised he would bring the bill to the floor for a vote.

Reid spokesman Jim Manley said Friday that the Senator remains committed to the bill.

“He strongly supports it,” Manley said. “He is anxious to get this bill to the floor.”

Timing is key, Norton writes: “What supporters most need now is to move the tremendous momentum the [bill] has achieved for a final vote in the Senate before the August recess.”

Sponsored by Sens. Joe Lieberman (ID-Conn.), Orrin Hatch (R-Utah) and Bob Bennett (R-Utah), the bill grants Democratic-leaning D.C. a full vote in the House while also giving a fourth seat to Republican-leaning Utah, which just missed getting an additional Representative following the 2000 Census.

A similar version of the measure passed the House in April; the Senate bill passed the Lieberman-chaired Homeland Security and Governmental Affairs Committee in a bipartisan vote in June.

Although supporters have praised the measure’s compromise nature, opponents have argued it is unconstitutional because it grants a non-state Congressional representation.

Those opponents include Senate Minority Leader Mitch McConnell (R-Ky.), who aides have said has not ruled out using a filibuster to prevent the bill’s passage.

Knowing this, voting rights advocates have spent the past several weeks lobbying key Republicans on Capitol Hill in an attempt to get the 60 votes needed.

In her letter, Norton outlines some of those activities, which included visits to Senate offices by Republican Rep. Tom Davis (Va.), who crafted the D.C.-Utah compromise aspect of the bill and co-sponsored the House version with Norton.

Other activities included a radio address by former Rep. Jack Kemp (R-N.Y.), several staff briefings led by constitutional experts, outreach to editorial boards around the country and Wednesday rallies near the Capitol.

Lieberman and Hatch also have stepped in to rally their fellow Senators. The duo sent out a “Dear Colleague” letter asking for support, and Hatch’s office is scheduled to host a staff-only meeting today outlining what supporters see as the constitutional basis for the bill.

A Democratic committee aide said last week that supporters are optimistic about the bill’s chances.

The lobbying already has secured some Republican support from Senate Governmental Affairs ranking member Susan Collins (Maine), and committee members Norm Coleman (Minn.) and George Voinovich (Ohio) voted for the bill at the June markup.

Other Republicans who advocates have targeted include Sens. Arlen Specter (Pa.) and Olympia Snowe (Maine).

Ilir Zherka, executive director of advocacy group DC Vote, said Friday that he is confident the bill has a good chance of passing the Senate once it hits the floor.

“It’s very fluid right now,” Zherka said. “But we’re within striking distance of getting more than 60 votes.”