From an office two blocks past the Capitol South Metro station, the chairman of the House Government Reform Committee has nudged back to life a conversation that has as much to do with the future of local government as it does with buying rail cars.

The bill that Rep. Thomas M. Davis III (R-Va.) introduced last month offers a $1.5 billion icebreaker to a region of winding jurisdictional lines and often clashing interests. But to win the money to finance a decade of improvements to the aging Metro transit system, political leaders in the Washington area's patchwork of cities, counties and states must do something they are not always good at: cooperate.

So far, the conversation has been civil, even upbeat. There seems to be an authentic hope among both Democratic and Republican officials that Davis's plan might goad the region's leaders to action on guaranteeing a dedicated source of revenue to operate Metro, which is what the bill demands of them in exchange for the $1.5 billion in federal aid.

"It's a real step forward that he dropped the bill and has basically called the question," said Gregory M. McCarthy, legislative affairs chief for D.C. Mayor Anthony A. Williams (D). "This is a wake-up call that we need to do something, and be bold, and it needs to be done on a regional basis."

State transportation secretaries in Maryland and Virginia, appointed by a Republican and a Democrat, said their successes in some instances of cross-Potomac cooperation bode well for the region's chances to preserve its heavily used transit system.

But some who have followed such efforts are skeptical.

In reality, said Dorn C. McGrath, a professor emeritus of regional planning and geography at George Washington University, "it pretty much is each jurisdiction for itself."

"The record is not one to be proud of," he said, citing traffic tie-ups, scattered construction patterns and damaging algae blooms in the Chesapeake Bay fed by pollution.

"It takes real political leadership to get something like this going," McGrath said. "No technician will tell you how to do that. Political leadership that favors -- or believes in -- planning is not popular."

Several proposals for Potomac River crossings and bistate highways around Washington have foundered in part because the leaders of the jurisdictions involved did not agree on their value.

In 2003, the U.S. Supreme Court had to settle a dispute over whether Maryland could prevent Virginia from extending a water pipe into the Potomac.

Even planning for the new Woodrow Wilson Bridge, a project considered vital by the governments involved, was caught up in several disputes between Maryland and Virginia over the division of responsibilities and costs.

Metro, with its 106 miles of track and 140 miles of bus routes, is a complex institution. No one legislature, governor or mayor has the power to act on behalf of the region in creating a permanent source of revenue for Metro.

The governments that finance Metro already face significant challenges in funding transportation priorities that are entirely within their borders, such as the rail-to-Dulles project in Northern Virginia or the intercounty connector in the Maryland suburbs.

Which government would take the lead in proposing to divert some of the revenue it gets from a current tax to support the region's transit system, or to impose a tax for that purpose?

Political leaders planning their early strategies in the dense heat of August say they can see the outlines of an approach to the Davis challenge. Advocates of increased transportation spending want to use his requirement for regional action to loosen political stalemates.

The result could be different-flavored funding guarantees in each major area, something Davis said would be fine by him.

McCarthy, for instance, said D.C. officials could look favorably at a 0.5 percent sales tax increase to fund Metro.

It "is something we should seriously consider and look at, and he's inclined to support it," McCarthy said of the mayor. A panel of government and business advisers recommended adopting such a plan regionwide.

But McCarthy also said that Williams agreed with D.C. Council Chairman Linda W. Cropp (D) when she said the District should not be stuck covering too big a slice of Metro's budget. Some officials inside and outside the District worry that pushing that issue could muddy the regional bid.

"I think it's a mistake to piggyback that issue on a dedicated source of revenue, because we won't get far if we do that," said Fairfax County Board of Supervisors Chairman Gerald E. Connolly (D). "It's not irrational for people to want to do that, but at the end of the day, we have to solve the issue of long-term funding for Metro."

Connolly is also counting on the District to lead by example. He said he expects to see a sales tax bill before the D.C. Council soon, which he hopes will pressure state legislators in Richmond to take over more Metro funding, the bulk of which is covered by taxpayers in Northern Virginia.

"The local governments don't have the resources to continue to pony up," Connolly said.

Virginia Transportation Secretary Pierce R. Homer said a new Virginia governor and General Assembly next year would have to weigh in on the state's response. A change in transit funding or a tax referendum would need approval in Richmond. He said he expects a protracted discussion but is encouraged by past successes.

"The region has enormous and rapidly growing transportation needs. . . . We still have a long way to go to get better," he said. "But when it has focused on transportation problems, it has done a magnificent job of solving them."

Maryland Secretary of Transportation Robert L. Flanagan, meanwhile, said he sees "no bandwagon for imposing a new tax." But, he noted, a proposal to devote part of an existing sales tax to transit passed Maryland's House of Delegates, so that idea "at least had some credibility."

Flanagan said it was too early to settle on, or speak about, state strategy.

Flanagan and Homer, who met for lunch last week to discuss the Davis bill and other matters, said the cooperation on the Wilson Bridge project shows that the region's leaders have gotten better at getting along.

"For years, the prior governors of Maryland and Virginia were at each other's throats, and the project was crawling along. . . . The good news is the current officeholders have really done a terrific job of working together," Flanagan said.

For Montgomery County Council member Howard A. Denis (R-Potomac-Bethesda), the idea of coming together over Metro is no fuzzy fantasy of campfire kumbayas. During his 18 years in the Maryland Senate, he said, one of the most constructive things he did was pack up for regional overnight retreats in the tiny Virginia community of Airlie -- in rural and Metro-free Fauquier County -- to buttress support for the subway and outline its future.

"It was like a camp setting," Denis said. It offered a legislator from Montgomery a less-formal chance to bond in meeting rooms and over dinner with counterparts from Prince George's County, Virginia and the District. Those gatherings, and the "miraculous" feeling of seeing Metro stations emerge in such places as Bethesda that once seemed impossibly distant, help him frame today's debate over the transit system's future.

"It was a lot more difficult to start this thing from the beginning," said Denis, who is a staff member on the Government Reform Committee but had no role in crafting the Davis bill. "Now what we're trying to do, of course, is save the system, to keep it from crumbling. . . . It's almost like a last clear chance for the stakeholders to get their act together."

Denis is pushing the idea of an Airlie-type conference "so you don't talk to people by throwing hand grenades over the wall."

For Davis, the din has emerged as he hoped it would when he worked with local and federal officials to design the plan. "This didn't come from just some brainstorm on a bill," he said. "It's supposed to work."

Davis said his goal is passage in the fall, giving momentum to the bill's supporters in the Senate. The bill won't touch issues of how Metro funding is proportioned among the District and the states, he said: "The last thing I want to start is a regional war. We want to keep the region together."

His $1.5 billion enticement is meant to be a political, not just a financial, incentive, he said, adding that local officials have a ready-made argument. " 'Guys, we're leaving a billion and a half dollars on the table if we don't do this,' " he imagines them saying. "This is a pretty strong incentive. . . . Voters understand that."

Suzanne Morse, president of the Pew Partnership for Civic Change, a Charlottesville consulting and research group that advises local officials, described the effort at cooperation as a test for the region: "As trite as it sounds, we're greater together than we are separate. . . . If you can come together around this issue, can you come together on a whole range of issues?"

The $1.5 billion federal infusion called for in a House bill would go toward train, track and station maintenance and to relieve crowding.