To answer the safety question, I believe that the “rednecks” (who supposedly could never countenance a Black president) are so dispirited right now with their economic lot that they would likely welcome a change. (They don’t know it yet, but I think they can accept a change if that change is to their economic benefit).
If Obama were to be assassinated (as you are suggesting) it would be the “establishment” that does the deed (if he, as President, were to threaten their privilege) rather than any kind of racist nut-job. But it will probably be blamed on a racist nut-job.