After months of weighing the race, Ed Gillespie, former chairman of the Republican National Committee, has told Virginia Republicans that he will launch a bid against U.S. Sen. Mark R. Warner, giving the GOP a high-profile challenger to the popular Democrat.

Gillespie’s pronouncements to GOP leaders suggest the official launch could come soon; he is required by Virginia law to decide before Feb. 1.

“As I’ve made clear, I am talking to a lot of my fellow Republicans in Virginia about running against Mark Warner,” Gillespie said in an e-mail Thursday. “I’ve been encouraged by people all across our party and our commonwealth. The filing deadline is February 1st, so I will be announcing my intentions in the near future.”

Gillespie, who is also a former lobbyist, quietly began discussions with senior Virginia Republicans about the race in the summer. He accelerated his plans after November’s elections, when Democrats won the races for governor, lieutenant governor and attorney general. That sweep left the GOP with a thin bench for upcoming contests — including the 2017 governor’s race, which many Republicans previously thought would be Gillespie’s first campaign.

Republicans say Gillespie is well aware that Warner, with a campaign war chest of $7.1 million and the personal wealth to spend far more, will be a formidable opponent. The former governor frequently rates as the most popular statewide official in public opinion polls. But GOP strategists hope that the flawed rollout of the Affordable Care Act will drag down all Democrats who supported it, including Warner.

While Warner declined to comment, the Democratic Senatorial Campaign Committee issued a statement after the New York Times posted a story on Gillespie’s intentions Thursday afternoon.

“Virginians don’t want to elect a DC shadow lobbyist like Ed Gillespie who epitomizes the reckless and irresponsible Republican economic agenda,” Guy Cecil, DSCC executive director, said. “Gillespie won’t work to strengthen Virginia’s economy, cut the nation’s debt or work to find common ground in Washington the way Mark Warner has done, and Virginians know that.”

Before he can face Warner, Gillespie must win the Republican nomination at a state party convention — a method that can result in unpredictable results and often favors the most conservative candidates.

Two other Republicans — Shak Hill, a Centreville financial planner, and Howie Lind, a former Pentagon official and lobbyist from McLean — have already announced plans to run, although neither has Gillespie’s party connections or fundraising background.