What, you mean Putin would have been too scared to invade if Trump was leader of the free world?
Yes, we all are well aware Trump would have used his Jedi mind trick to dissuade Putin from invading. (The same powers of the mind he used to declassify top secret documents).
Though I think there is a small chance Putin wouldn't have felt the need for a military invasion as this war as much as anything is about geopolitical influence, especially in the former Soviet countries bordering Russia.
Let's not forget Putin was a KGB agent stationed in Berlin during the fall of the Berlin wall. He has witnessed firsthand the demise and influence of the Soviet Union, much to his on the record chagrin.
Putin (Russia) was too weak to do anything about the Baltic nations etc joining the E.U./NATO in the early 2000's but by 2008 when Georgia started making the same noises Putin invaded Georgia.
Once the pro E.U./NATO movement in Ukraine forced the pro Russian Yanokovych government to resign in 2014, Putin annexed Crimea and started a proxy war in the east of Ukraine.
So there is a chance that because Trump would have weakened pro E.U./NATO elements in Ukraine so much that Putin might not have felt the need for a full scale invasion. Not because of anything to do with any fear of what Trump might do or his unpredictability.
Though I wouldn't be surprised if Putin had long planned to invade and was hoping that strong ties with Germany with their dependence on Russian gas and Trump still being in power and weakening NATO/E.U. resolve would have made the task far, far easier.