That does look a lot like Trotsky

Edit: This prompted me to read a little about Kamenev, who I was vaguely familiar with from reading about the Purges as a sort of wrecker Ice Climbers pair with Zinoviev, but not even enough to recognize him in that picture though his visage is quite obvious. The Wikipedia page is pretty much exactly as dire as one would expect (including the amazing claim that the "show trials" were the product of "months of rehearsal," along with more grim and uncontestable things like several members of his family being executed). On the lighter side:

Before leaving Siberia [having been sent into exile by the Tsarist government], Kamenev proposed sending a telegram thanking the Tsar's brother Mikhail for refusing the throne. He was so embarrassed later by his action that he denied ever having sent it.