If this was not the political landscape, then why was nothing done after Giffords? Why not after Aurora? Or the Sikh Temple? Not only did the administration do nothing, the States were not overly concerned, either.
Sorry, but it was not the election or any of the above that gave the impetus to the current political atmosphere. The run on guns and ammo did not spike with any of those prior events.
With all due respect and at the risk of derailing the topic here, I suggest that the fundamental difference between the events you cite and the Sandy Hook incident was in fact the election.
While Sandy Hook itself might not have been predictable, it was a near certainty that there would be some incident post-election. I for one, believe that the present dynamic would have followed that incident and that the aggressive push for gun control was a foreseeable outcome of the president's re-election.