▁histor ians ▁explain ▁the ▁p urg es ▁by ▁the or izing ▁that ▁rival ▁fa ctions ▁explo ited ▁St alin ' s ▁par ano ia ▁and ▁used ▁terror ▁to ▁enh ance ▁their ▁own ▁position . ▁ ▁Peter ▁White wood ▁exam ines ▁the ▁first ▁pur ge , ▁directed ▁at ▁the ▁Army , ▁and ▁comes ▁up ▁with ▁a ▁third ▁interpretation ▁that : ▁ ▁St alin ▁and ▁other ▁top ▁leaders , ▁using ▁Marx ist ▁not ions ▁that ▁they ▁were ▁always ▁surrounded ▁by ▁enemies , ▁always ▁wor ried ▁about ▁the ▁vulner ability ▁and ▁loyal ty ▁of ▁the ▁Red ▁Army . ▁It ▁was ▁not ▁a ▁p loy ▁– ▁St alin ▁truly ▁believed ▁it . ▁“ St alin ▁attacked ▁the ▁Red ▁Army ▁because ▁he ▁seriously ▁mis per ce ived ▁a ▁serious ▁security ▁threat ” ; ▁thus ▁“ St alin ▁seems ▁to ▁have ▁genu in ely ▁believed ▁that ▁foreign ‐ back ed ▁enemies ▁had ▁in fil tr ated ▁the ▁ranks ▁and ▁managed ▁to ▁organ ize ▁a ▁consp i racy ▁at ▁the ▁very ▁heart ▁of ▁the ▁Red ▁Army .” ▁ ▁The ▁pur ge ▁hit ▁deeply ▁from ▁June ▁ 1 9 3 7 ▁and ▁November ▁ 1 9 3 8 , ▁removing ▁ 3 5 , 0 0 0 ; ▁many ▁were ▁executed . ▁Exper ience ▁in ▁carrying ▁out ▁the ▁pur ge ▁facil itated ▁p urg ing ▁other ▁key ▁elements ▁in ▁the ▁wider ▁Soviet ▁polity . ▁ ▁Histor ians ▁often ▁c ite ▁the ▁dis ruption ▁as ▁factors ▁in ▁its ▁dis astr ous ▁military ▁performance ▁during ▁the ▁German ▁invasion . ▁ ▁Foreign ▁relations ▁