Very unlikely at this stage Russia would do anything, but if it becomes very unstable in Turkey who knows. It's a close neighbour. Russia thinks it has a right in the region. America has its Monroe doctrine after all. Even the remote possibility of conflict between Russia and NATO over Turkey is something to worry about.
The idea of Trump as president has made me dwell more recently on the fragility of continued human existence in the nuclear age. I am very pessimistic about our prospects of surviving the century. In fact you could say we are lucky to have survived as long as we have. View any more years avoiding nuclear war as a kind of bonus, looking on the bright side.
Read this story recently about a strategist who asked US general what procedures were in place to stop an irrational president setting off a nuclear war. The answer was basically that there are no safeguards, the president can do as he wishes. The only safeguard against an irrational president is "not to elect one".