Some heavy hitters are backing the D.C. Council’s strategy for gaining budget autonomy in its pending lawsuit against Mayor Vincent Gray, arguing that Congress has proved unable to address the issue.

Former two-term D.C. Mayor Anthony Williams joined former Rep. Thomas M. Davis III, a Virginia Republican who chaired the House Oversight and Government Reform Committee, and senior Brookings Institution Fellow Alice Rivlin in an amicus brief supporting the District’s fiscal freedom from Congress.

“The need for congressional approval of D.C.’s budget distorts the budgeting process, costs local taxpayers millions of dollars every year, and creates a destructive uncertainty about the provision of basic services when partisan politics leaves the federal government’s own financial decisions in disarray,” they argue in a 13-page brief filed in federal court on May 2.

Rivlin, the founding director of the Congressional Budget Office, a former vice chairwoman of the Federal Reserve Board and director of the White House’s Office of Management and Budget under the first Clinton administration, is an expert on fiscal policy. She also headed the Financial Control Board in the 1990s, an entity that current D.C. Chief Financial Officer Jeffrey S. DeWitt argues the feds could bring back if D.C. moves forward with the voter-approved referendum. Williams was the city’s first CFO. Davis is a long-time proponent of greater autonomy for the District.

The brief cites failed attempts at budget autonomy legislation, including the 2012 bill sponsored by then-Senate Homeland Security and Governmental Affairs Chairman Joseph I. Lieberman, I-Conn., and ranking member Susan Collins, R-Maine, as proof that the principle enjoys widespread bipartisan support around Capitol Hill, but continues to be held hostage by a do-nothing Congress. House Majority Leader Eric Cantor, Oversight and Government Reform Chairman Darrell Issa and former Rep. Jo Ann Emerson of Missouri are among the Republicans name-checked as supporters in the brief.

“Budget autonomy has been yet another casualty of the current partisan gridlock,” it states. “It was in light of this political climate — and fearing that its finances could yet again be held hostage as a result — that the District sought an alternative route to budget autonomy.”

The brief urges the court to enforce the local law, approved in an April 2013 referendum by more than 80 percent of D.C. voters, but it does not address the legal issues of the case, including whether D.C. has the authority to amend the appropriations process laid out in the Home Rule Act.

D.C. Attorney General Irvin B. Nathan, who is defending the mayor in the suit, says only Congress can amend the budget process. During a May 2 appearance on WAMU’s “Kojo Nnamdi Show,” Nathan maintained that nothing has shifted in D.C.’s relationship with congressional appropriators.

“. . . The only way to change it is by an act of Congress, which has been recognized by all prior councils because they have repeatedly gone up to the Hill and requested budget autonomy from the Congress,” Nathan said. “It’s obvious that they have tired of that and they’ve decided to take the law in their own hands and pass this provision of a Budget Autonomy Act, which the legitimacy of which will now be resolved in court. And we welcome that court resolution.”

Nathan, who served as the House’s general counsel prior to his 2011 appointment with the city, said it is not accurate to say that Congress did nothing to stop budget autonomy since the city voted for it last year. A House Republican requested the Government Accountability Office weigh in on the law, Nathan pointed out, and the nonbinding opinion backs his office’s stance that the local law is null. Nathan also said he had no interest in and no obligation to promote the interests of his former employer.

“I’m trying to protect the District of Columbia,” he said. “And in particular, the representatives of the District of Columbia — the 33,000 employees who would be subject to criminal and other sanctions if they were to follow what this council has done.”

Gray has recruited some top-notch legal help. Clinton-era Solicitor General Seth P. Waxman, who has delivered more than 65 arguments to the Supreme Court, will serve as his personal counsel in the case.

Judge Emmet G. Sullivan, who previously presided over the late Sen. Ted Stevens’ federal corruption trial, will hear the case on May 14. He is a Clinton appointee to the U.S. District Court who previously served as a Superior Court and D.C. Appeals Court judge.

Sullivan has indicated that he aims to give both sides a resolution before the critical dates in the budget season. He will first decide if the case has jurisdiction in federal court, then rule on the merits of the case. Gray has already proposed his spending plan for the next fiscal year, and the council is set to have its first vote by May 28.

Nathan indicated that more briefs from individuals who doubt the law’s legitimacy may be on the way. Two other briefs backing budget autonomy were entered in court on Monday.

DC Appleseed, DC Vote and three other local advocacy organizations that supported the charter amendment process filed a 22-page brief explaining why the Gray administration is required to abide by the local law. They argue that by refusing to do so, city officials are violating the Constitution.

A coalition of “concerned legal professionals,” comprised of lawyers from many of the city’s most prominent firms, filed a brief that walks the court through the history that lead up to President Richard M. Nixon signing the Home Rule Act in 1973. It does not address the merits of the dispute. Instead, the 22-page document recaps how progress on civil and voting rights across the country helped turn the tide toward greater self-governance in the District.

If similar energy catches hold, as Senate Homeland Security and Governmental Affairs Committee staff have suggested it might, the lawsuit would be moot.

Attorney Karen L. Dunn, one half of pro bono legal team marshaled by the D.C. Council, said the lawsuit puts budget autonomy “front and center, and perhaps makes it more top of mind for folks in Congress.”

“I think particularly the filings in this case will make clear that there is broad support [at all levels] for budget autonomy,” Dunn said in an interview.