This will certainly give the anti-Second Amendment nuts fresh ammunition, as well as the Left overall, to change the subject from their post-midterm election recriminations. The only thing that prevents it from being "Gabby Gifford II" - which took place closely following the Dems' 2010 midterm disaster - is that the only fatality was the gunman himself:
A gunman targeted three downtown public buildings — the Mexican consulate, federal courthouse and police headquarters — before police shot and killed him, according to local media reports. Police said the unidentified man was suspected of opening fire on buildings at around 2:30 a.m. local time [November 28th, 2014], KVUE-TV reports. The Austin American-Statesman reported that the Mexican consulate and federal courthouse were among the target locations, as well as the police building. Assistant Chief Raul Munguia told reporters that the suspected shooter, who was wearing a vest, was killed near his vehicle, which may have contained an improvised explosive device. The police bomb squad was on the scene.
The fact that this maniac targeted the Mexican consulate in Austin is a propaganda godsend to the Obama White House. You can count on The One using this incident to smear amnesty opponents - which is to say, (currently) three quarters of the American electorate - as "crazed, violent, racist, rightwing extremists" who must be "put down" for the public good. Or words to that effect. Along with the gun control angle, it's a propaganda blue plate special.
I'll leave it to you to speculate on whether GOP opposition to O's unlawful amnesty decree will diminish or crumble altogether going forward. My guess is it will rally the Donk base somewhat, but will have little effect on Republican determination, such as it is, given his infernal majesty's squandered credibility and grotesque ubiquity. But he'll give it his best demidivine shot.