I am a firm believer that self preservation is the best motivation. If Republicans still think that having lots of pissed off people with easy access to guns is a great idea, then I doubt us liberals pontificating on gun control will change their minds.
While I am not a Republican taking your comment related to easy access to guns to it's logical conclusion you are (perhaps?) referring to a change in gun laws that resulted in citizens not having easy access to guns, that being legal private ownership.
I'm a firm proponent of the 2nd amendment but at the same time getting really sick of firearms, which are really tools albeit deadly as that's a main purpose, being misused by the sick to perpetrate public shootings.
But I have yet to read a single solution that if enacted before hand would have 100% prevented the shooting and allow lawful citizens to continue enjoying their 2nd amendment rights that inevitably results in gun control discussions and proposals which is depressing.
Lawful owners will always be able to say that it's not their fault, so why should they give up a revered constitutional right? And they're right.
So I think we're stuck with the status quo and it will take societal changes and not a massive change in gun control to affect the status quo in regards to these shootings.