2 2 ▁June ▁ 1 9 4 1 . ▁During ▁the ▁war , ▁he ▁also ▁commanded ▁an ▁inf antry ▁division ▁in ▁the ▁Balt ic ▁for ▁three ▁years . ▁ ▁He ▁went ▁on ▁a ▁military ▁career ▁and ▁reached ▁high ▁ranks ▁during ▁World ▁War ▁II . ▁After ▁the ▁war , ▁being ▁a ▁decor ated ▁veter an , ▁he ▁left ▁active ▁career ▁and ▁taught ▁at ▁the ▁F run ze ▁Military ▁Academy , ▁reaching ▁the ▁rank ▁of ▁a ▁Major ▁General . ▁ ▁In ▁ 1 9 4 9 , ▁Gr ig oren ko ▁def ended ▁his ▁Ph . D . ▁th esis ▁on ▁the ▁theme ▁" Fe atures ▁of ▁the ▁organization ▁and ▁conduct ▁of ▁combined ▁off ensive ▁battle ▁in ▁the ▁mountains ." ▁ ▁In ▁ 1 9 6 0 , ▁he ▁completed ▁work ▁on ▁his ▁doctor al ▁th esis . ▁Over ▁ 7 0 ▁of ▁his ▁scientific ▁works ▁on ▁military ▁science ▁were ▁published . ▁ ▁D iss ident ▁activities ▁ ▁In ▁ 1 9 6 1 , ▁Pet ro ▁Gr ig oren ko ▁started ▁to ▁open ly ▁critic ize ▁what ▁he ▁considered ▁the ▁excess es ▁of ▁the ▁K hr ush chev ▁regime . ▁He ▁maintained ▁that ▁the ▁special ▁privileges ▁of ▁the ▁political ▁el ite ▁did ▁not ▁comp ly ▁with ▁the ▁principles ▁laid ▁down ▁by ▁Len in . ▁Gr ig oren ko ▁formed ▁a ▁diss ident ▁group ▁— ▁The ▁Group ▁for ▁the ▁Str ug gle ▁to ▁Rev ive ▁Len in ism . ▁Soviet ▁psych iat rist s ▁sitting ▁as ▁leg ally ▁constit uted ▁comm issions ▁to ▁in quire