Now would be good timing. The base is more pissed off than ever and they still haven't forgotten about sandy hook. It would also help deflect from a whole lot of the messy issues surrounding the Zimmerman trial. Does anyone think that if Zimmerman wasn't armed, either he or Trayvon would have died that night? I don't, and I bet most people think likewise.
Politically, it's a great opportunity to do something that would truly help prevent things like this from happening. It would push forth a cause that all liberals would be happy to rally around and declare a major victory for Obama. it would be keeping a promise to sandy hook that they have not been forgotten, and letting the black community know Trayvon losing his life ultimately helped save many more.
He could force the republicans hand between this and immigration. But I'm not confident in Obama's ability to seize a moment like this.