** FILE ** Philadelphia Mayor Michael A. Nutter, center, flanked by Brady Campaign to Prevent Gun Violence President Dan Gross, left, and New York City Police Commissioner Raymond Kelly, speaks outside the White House in Washington, Wednesday, Jan. 16, 2013, following President Barack Obama's proposal to reduce gun violence. (AP Photo/Susan Walsh)

Photo by: Susan Walsh

** FILE ** Philadelphia Mayor Michael A. Nutter, center, flanked by Brady Campaign to Prevent Gun Violence President Dan Gross, left, and New York City Police Commissioner Raymond Kelly, speaks outside the White House in Washington, Wednesday, Jan. 16, 2013, following President Barack Obama's proposal to reduce gun violence. (AP Photo/Susan Walsh)