When a pair of Colorado lawmakers were recalled last month in a referendum on gun control, opponents had this to console them: At least, they said, the twin defeats did not alter the balance of power in Denver, the state capital. Now gun rights advocates are looking to change that. Organizers have received official go-ahead to start gathering signatures in a bid to oust state Sen. Evie Hudak, a Democrat from the Denver suburb of Westminister, who was the target of a failed recall petition drive earlier this year. The group, certified by Colorado’s secretary of State, has until Dec. 3 to collect just over 18,900 signatures to force a vote. The stakes: control of the state Senate, which Democrats hold by a tenuous 18-17 edge. Hudak, who is in her second term, was one of four lawmakers originally targeted after the Democratic-controlled Legislature passed a series of sweeping gun controls in response to mass shootings last year in Aurora, Colo., and Newtown, Conn. The measures, signed into law by Democratic Gov. John Hickenlooper, include a requirement for universal background checks and a limit on ammunition magazines like the one used in the July 2012 theater shootings in Aurora, another suburb of Denver.