▁they ▁consist ently ▁maintain ▁a ▁strong ▁influence ▁over ▁success ive ▁U . S . ▁govern ments . ▁As ▁a ▁result , ▁he ▁arg ues ▁that ▁U . S . ▁foreign ▁policy ▁has ▁focused ▁on ▁gain ing ▁and ▁maintain ing ▁un rest rict ed ▁access ▁to ▁mark ets , ▁energy ▁supplies , ▁and ▁strateg ic ▁resources ▁across ▁the ▁world . ▁Ch om sky ▁goes ▁on ▁to ▁categor ize ▁the ▁specific ▁purposes ▁of ▁the ▁doctrine ▁as : ▁ ▁containing ▁other ▁cent ers ▁of ▁global ▁power ▁within ▁the ▁" over all ▁framework ▁of ▁order " ▁managed ▁by ▁the ▁United ▁States ; ▁maintain ing ▁control ▁of ▁the ▁world ' s ▁energy ▁supplies ; ▁bar ring ▁un accept able ▁forms ▁of ▁independent ▁national ism ; ▁and ▁over coming ▁" c ris is ▁of ▁dem ocracy " ▁within ▁domestic ▁enemy ▁territory . ▁ ▁Ch om sky ▁arg ues ▁that ▁as ▁a ▁part ▁of ▁this ▁strategy , ▁the ▁U . S . ▁has ▁regularly ▁engaged ▁in ▁" prevent ative ▁war ", ▁which ▁he ▁highlight s ▁is ▁illegal ▁under ▁international ▁law ▁and ▁could ▁be ▁categor ised ▁as ▁a ▁war ▁crime . ▁Pre vent ative ▁war ▁refers ▁to ▁conflict ▁w aged ▁to ▁prevent ▁a ▁nation ▁ever ▁reaching ▁the ▁stage ▁where ▁it ▁could ▁become ▁a ▁potential ▁threat , ▁and ▁according ▁to ▁Ch om sky , ▁under ▁the ▁reg imes ▁of ▁Ron ald ▁Re agan , ▁George ▁H . W . ▁Bush ▁and ▁his ▁son ▁George ▁W . ▁Bush ▁it ▁has ▁act ively ▁involved ▁attack ing ▁" an ▁imag ined ▁or ▁invent ed ▁threat