 Volkogonov believed that Stalin's Marxism was shaped by his "dogmatic turn of mind", suggesting that this had been instilled in the Soviet leader during his education in religious institutions.According to scholar Robert Service, Stalin's "few innovations in ideology were crude, dubious developments of Marxism".Some of these derived from political expediency rather than any sincere intellectual commitment; Stalin would often turn to ideology "post hoc" to justify his decisions.