▁of ▁the ▁German ▁a cademy , ▁bel ieving ▁in ▁the ▁" ide as ▁of ▁ 1 9 1 4 ," ▁and ▁signing ▁national ist ▁pet itions . ▁He ▁then ▁was ▁draft ed ▁into ▁the ▁army , ▁working ▁for ▁the ▁Kriegs pres se amt , ▁the ▁public ▁relations ▁office ▁of ▁the ▁army . ▁ ▁Political ▁career ▁ ▁After ▁Germany ' s ▁defeat ▁in ▁ 1 9 1 8 ▁and ▁his ▁dem obil ization ▁from ▁the ▁army , ▁Ros enberg ▁joined ▁the ▁new ▁Independent ▁Social ▁Democratic ▁Party ▁( US PD ). ▁He ▁went ▁on ▁to ▁join ▁the ▁Commun ist ▁Party ▁of ▁Germany ▁( K PD ) ▁in ▁ 1 9 2 0 . ▁ ▁Ros enberg ▁emer ged ▁as ▁an ▁important ▁the or etic ian ▁for ▁the ▁diss ident ▁left ▁wing ▁of ▁the ▁K PD ▁in ▁their ▁on going ▁fa ction al ▁struggle ▁with ▁the ▁party ▁leadership ▁head ed ▁by ▁Heinrich ▁Brand ler ▁and ▁August ▁Th al heimer . ▁He ▁was ▁regarded ▁as ▁one ▁of ▁the ▁top ▁leaders ▁of ▁the ▁party ▁left ▁in ▁the ▁city ▁of ▁Berlin ▁and ▁was ▁an ▁advoc ate ▁of ▁the ▁theory ▁that ▁the ▁K PD ▁should ▁purs ue ▁a ▁revolution ary ▁off ensive ▁against ▁the ▁We imar ▁state . ▁ ▁The ▁left ▁wing ▁gained ▁control ▁of ▁the ▁K PD ▁in ▁April ▁ 1 9 2 4 ▁and ▁Ros enberg ▁was ▁elected ▁a ▁member ▁of ▁the ▁gover ning ▁Central ▁Committee ▁of ▁the ▁party ▁as ▁well ▁as ▁a ▁delegate ▁to ▁the ▁ 5 th ▁Congress ▁of ▁the ▁Commun ist ▁International ▁and ▁a ▁member