If there was enough traction you can bet your ass it would have been in the joke "Stimulis" bill (just like the stealth health care dictator) - the fact it wasn't means 1) isn't on the agenda for the foreseeable future 2) congresscritters are scared of it (hoping).
If there is infighting, it means that congress is afraid of losing their seats in contested areas. This isn't a "must pass" at the moment, most people don't give a shit.
Then again, Sarah Brady prays every single night for the next Virginia Tech. In reality, that is what they are probably waiting for. They aren't brave enough to just go after it, they need a real "reason" to (way to justify it). Mexcio's problems aren't something anyone cares about. Next big shooting? Watch out.