As the debate over President Barack Obama's proposed gun legislation heats up on Capitol Hill, gun control advocates have a potential ace in the hole: Former Rep. Gabrielle Giffords, D-Ariz., the victim of a horrific incident of gun violence that interrupted a once-promising political career, is about to become eligible to lobby.

For Giffords, tomorrow marks the end of the official one-year "cooling off" period that former House members face when they leave office before they can lobby their former colleagues, according to Sunlight's post-employment lobbying tracker. Should she wish, she will be permitted to register as a lobbyist, meaning she will no longer be prohibited from "seek(ing) official action from any current Member, officer, or employee of either the Senate or the House, or from any current employee of any other legislative office." Giffords resigned her seat to focus on recovery from brain injuries suffered when she was a victim of a shooting in Tucson, in which six people died and twelve others were injured. But following the massacre of 20 schoolchildren and six adults in Newton, Conn. last month, she launched a super PAC, Americans for Responsible Solutions, to lobby for gun control.

MORE: For data on the gun debate, see the Sunlight Foundation's resource page.

Whether she'll choose to take her advocacy for gun laws personally to the halls of Congress remains to be seen. Her office did not return a call for comment. According to news reports, the super PAC she founded with her husband, retired astronaut Mark Kelly, hopes to raise $20 million to spend in the 2014 congressional elections, to put it on par with the National Rifle Association (NRA). However, the group has not yet reported lobbying expenses and it is not clear if its strategy will include such activity in addition to spending on elections.

Last year, the NRA and other gun rights groups reported hiring 42 lobbyists  including a former member of Congress, Rep. Allen Boyd, D-Fla., to plead their case in Washington. In contrast, gun control groups reported paying eight lobbyists.

The gun debate is gaining intensity on Capitol Hill following last year's tragic shootings at Sandy Hook elementary school, which left 20 children and six adults dead. Obama announced a package of executive actions and legislative proposals earlier this month, following deliberation by a task force led by Vice President Joe Biden. Today Sen. Dianne Feinstein, D-Calif., plans to introduce legislation to outlaw assault weapons, which were among the guns used by shooter Adam Lanza in the Newtown shooting. This week, a New Mexico teenager allegedly used an assault weapon in an attack on his family, killing his parents and three siblings.

The next lawmaker eligible to register to lobby after Giffords is former Rep. Jay Inslee, D-Wash., on March 20, according to Sunlight's post-employment tracker. Inslee, however, is unlikely to do so as he was recently elected governor of Washington. Numerous top former congressional staff, who are also restricted from certain lobbying activities for one year after leaving Capitol Hill. Former senators are required to wait two years before lobbying Congress.