Several witnesses and victims of the Jan. 8, 2011 shooting are signing on to a new political effort to get presidential candidates to solve the problem of gun violence.

They appear in a TV ad that asks President Barack Obama and former Governor Mitt Romney to end their 18 months of silence on the issue.

One of the victims in the ad is Pam Simon, a former aide to U.S. Rep. Gabrielle Giffords. Simon was shot twice during the Congress on Your Corner event at which six people died and 13 were wounded, including Gifffords.

Simon is joining the political cause "because 48,000 Americans will be murdered with guns during the next president's term," Simon says in the ad, imploring the candidates to come up with a plan to deal with gun violence.

She is followed by Col. Bill Badger, also injured in the shooting.

"That's three Aurora shootings every day," he says in the ad.

They and nine others sign on to the message at the end of the ad, and have also signed the bottom of a print ad paid for by the group Mayors Against Illegal Guns.

New York Mayor Michael Bloomberg started the political committee years ago and hundreds of mayors have signed up as members, including Phoenix Mayor Greg Stanton.

Simon says she did not get involved in political causes while she worked as an aide to Giffords, but after she retired in June she decided to join other survivors of the shooting.

“We need to make this country safer from guns being in the wrong hands," she says.

While she wasn't active in the issue before, gun violence has impacted her life for years, she says. Simon was a teacher in Arizona during the Columbine shooting in a Colorado high school in 1999, and she says her students did training exercises about what to do if a gunman enters the classroom.

Watch the Mayors Against Illegal Guns ad: