Is the District of Columbia, the capital of the United States and the free world, becoming a suburb of the economic powerhouse a few miles west?

With the growth of Tysons Corner ... err ... Tysons, Fairfax County leaders seem to think so.

Fairfax County business leaders gathered in a conference room at Gannett’s headquarters last week to discuss “the new city centers” envisioned around the Silver Line Metro stations being built.

Gerald L. Gordon, president of the Fairfax County Economic Development Authority, didn’t pull any punches. Working through a slide show showing the county’s growth over the past 30 years, Gordon said Fairfax County had become the economic center of the region.

Then he broke out this line: “Fairfax County is now the downtown. D.C. just became our suburb.”

A westward-looking view of the Silver Line of the Metro system as it passes through Tysons Corner along Leesburg Pike. (Jahi Chikwendiu/WASHINGTON POST)

Gordon wasn’t alone. Holland & Knight Partner Stuart “Stu” Mendelsohn, a former Fairfax County supervisor and longtime member of the task force that shaped the vision for Tysons, repeated Gordon’s remark minutes later. Keith Turner, an executive at Tysons developer CityLine Partners, then compared Scotts Run Nature Preserve (384 acres) to Rock Creek Park (1,754 acres).

The argument goes like this: Fairfax County has far more Fortune 500 companies (nine vs. four), enjoys a much lower unemployment rate (4 percent vs. 8.7 percent), is bookended by two airports and, with Metro arriving, is slated to add dozens of buildings taller than anything in the District. And, the Virginia community is a battleground in the presidential election.

When the Tysons projects that have been submitted for approval are complete, Tysons alone will have 50 million square feet of office space, 35 million square feet of residences and 5.5 million square feet of hotels. By those measures, it will become a major U.S. city.

Some District leaders consider Tysons a threat. The Downtown D.C. Business Improvement District, a group funded by commercial property owners, ranked the arrival of Metro to Tysons as one of its top concerns in its 2011 annual report. Office space in Tysons is available at a huge discount — about $25 a square foot less — compared with the average downtown.

But Pedro Ribeiro, spokesman for D.C. Mayor Vincent Gray, scoffed at talk of a rivalry. “We don’t consider Fairfax County to be our competition,” he said. “New York City is our competitor. San Francisco is our competitor. They’re not even in the same league.”

Ribeiro was not even aware that four Silver Line stations were coming to Tysons; he thought there would only be one. (The District has 40.)

“I think somebody really needs to go look up in a dictionary what the definitions of suburban and urban are,” Ribeiro said. “And then maybe we can have a discussion.”