The idea of Anti-Putin coalition is discussed since the beginning of century 21
The Anti-Putin coalition becomes important since the Russian invasion into Georgia in 2008 and, especially, since the Russian invasion into Ukraine in 2014. Since that, the analogy between Putin and Hitler becomes evident, and many authors indicate that the only heavy economical sanctions and strong military action may stop the Putin's expansion and prevent the new world war.
2013.09.09. http://www.aei-ideas.org/2013/09/moscow-mayoral-election-shows-the-anti-putin-coalition-still-alive-and-well/ Moscow mayoral election shows the anti-Putin coalition still alive and well. Leon Aron | September 9, 2013, 11:53 am
2014.05.14. https://news.pn/en/politics/103855 Parubiy compared Putin to Hitler and urged the world to create the coalition against the president of Russia. 11 May 2014 20:17.