Washington (CNN) - A former aide to retiring Republican Rep. Frank Wolf of Virginia Tuesday is officially jumping into the race for his U.S. House seat, which will be among the most contested and expensive congressional battles in this November's midterm elections.
Three-term state delegate Barbara Comstock will formally declare her candidacy Tuesday morning, her campaign told CNN.
"I have won THREE races in one of the most competitive areas of the 10th District and our trademark has been that we have never been outworked," said Comstock in a fundraising email obtained by CNN.
Wolf, first elected in 1980 announced last month that he'll retire at the end of 2014 rather than run for re-election. The 10th Congressional District, located in the suburbs and exurbs of Washington, D.C in northern Virginia, was already considered a swing area in what has become a battleground state. In the 2012 election, GOP presidential nominee Mitt Romney narrowly won the district, but then-Sen. Barack Obama prevailed there four years earlier.
Comstock, in her third term representing parts of Loudon and Fairfax counties in Virginia's House of Delegates, takes conservative stands on many issues, from business regulations to gun control. She opposes abortion rights, but advocates making birth-control pills easier to obtain.
Comstock narrowly won re-election last year but raised more campaign cash than any other candidate for the House of Delegates.
The only other Republican candidate to enter the race so far is notorious White House "party-crasher" Tareq Salahi, who was also a write-in candidate last year for governor of Virginia.
National Democrats see Wolf's retirement as a pick-up opportunity. Democrats need to win back a challenging 17 House seats from the Republicans next November to grab control of the chamber.