I'm a third of the way through Stephen Kotkin's excellent Stalin: Volume I: Paradoxes of Power, 1878–1928 and between the years 1905 to 1917, it seems as if Stalin was exiled to Siberia, escaped, recaptured, and subsequently exiled at least five different times, almost always by the Ohranka. After so many repeated escapes and rearrests, why didn't they just execute him? If an answer exists that is indeed exclusive to Stalin, than I'd extend my question to his revolutionary peers, who seem to possess the same pattern of exile, escape, repeat.