well). But, Doyle argues, imperial expansionsnare in reality extremely complicatednand extremely varied in nature.nMoreover, recent researchersnhave tended to underline this complexitynand variety by pointing outnpossible important factors in imperialnexpansion other than the disposition ofn”the metropole” itself to expand:nnamely, the actions of “the periphery,”nand the nature of “the internationalnsystem” which the metropolenconfronts.n”Pericentric” theories of empire findnthe source of imperial expansion notnso much in “the metropole” as in thencharacter and behavior of the peripherynthat borders the metropole. Herenon the periphery we often find weaknand turbulent states, or weak but aggressivenstates (unaware, that is, ofntheir own relative weakness). Suchnstates may compel intervention, innorder to restore order or to protect anfrontier; or factions within such statesnmay actually invite intervention, innorder to retain their own threatenednpower. But in either case, it is not onlynthe motives and actions of the metropolenwhich are decisive.nThe great virtue of such “pericentric”ntheories is that with them we arenno longer confronted by evil “aggressors”nand passive, innocent “victims”n(moral categories), but merely by internationaln”actors” of various sorts.nBut while Doyle finds the “pericentric”napproach a useful corrective tonthe pure metrocentric theories, he alsonthinks (rightly, it seems to me) that itnsometimes goes too far. “Pericentric”ntheories tend to ignore the pressurenthat comes from the metropole, a pressurenwhich metropoles do often tend tonimpose on peripheries, even thoughnthe nature and the behavior of thenperipheries may also seem to “invite”nit.nDoyle is more impressed by then”international-systems approach” as ancorrective to the metrocentric theories.nThe advocates of this approach arguenthat imperial expansion can be explainednsimply by combining the factualndisparities of power between statesnwith the existence of a prevailing internationalnanarchy. Each state, they suggest,nhas identical strivings towardsngrowth and power, and identical fearsnof decline and weakness; they strugglenand compete against one another in anworld without rules. Those states thatnare (for whatever reason) “more capable”ninevitably begin to exert influencenand power over those states that aren(for whatever reason) “less able.” Andnthis makes sense, since the internationalnsystem basically offers states onlyntwo choices: to dominate, or to bendominated. Imperial domination isntherefore merely a natural and necessarynresult of relations between powerfulnand weak states, in an atmospherenof tense and ferocious internationalncompetition. In addition, imperialndomination is, in the absence of anyninternational guarantor of order, a perfectlynnatural and explicable exercisenin self-defense.nAs with the “pericentric” theories,nthe virtue of this approach is that oncenmore we remove ourselves from anworld of moralizing polemic (evil “aggressors”nand innocent “victims”). Insteadnwe simply see many differentn”actors,” all with similar impulses, butnwith different capabilities. And then”international systems” approach doesngive due weight to the power naturallynexerted by metropoles.nIt seems pretty obvious that the bestnway to approach any specific imperialnexpansion is to see it as a mix ofn”metropolitan,” “peripheral,” and “internationalnsystem” elements—a mixnthat will probably vary widely with thenempire under discussion. At leastnDoyle has provided us with a coherentnintellectual structure within which wencan begin the dispassionate analysis ofnany particular imperial advance. This,nneedless to say, represents a long conceptualnstep forward (as can be seen innDoyle’s own highly complex discussionnof “The Scramble for Africa,”nwhich takes up the last half of thenbook).nBut towards the end of his discussionnof theory, it comes to Doyle like anrevelation that the key to understandingnthe growth of empires may well benthat some states simply are better constitutednthan others, internally, tonwithstand the pressures of the internationalncompehtion. They simply seemnto be more politically stable and betternorganized. And this internal situationngives them a great natural advantagenin the ups and downs of internationalnstruggle.nWhat is striking about Doyle’s insightnhere is that it is hardly new. Onnnnthe contrary, it is (unknown to Doyle)nancient. Thus Polybius, the Greek historiannof Rome’s rise to world power,nbroke off his narrative of the HannibalicnWar after the Roman disaster atnCannae; at this point he presented (innhis famous Sixth Book) the reason whynRome not only recovered from militaryncatastrophe but went on to conquernthe world: It was the stability andnorder provided by Rome’s constitution.nThis “mixed constitution,” accordingnto Polybius, was the best politicalnconstitution of any state existing innhis own time. It gave the RomannRepublic an enormous natural advantagenin her competition with the othernMediterranean states, generating anninternal stability that enabled Rome tonabsorb shocks and take on tasks thatnmight have shaken other governments.nThis, precisely, is Doyle’s insight—nbut Polybius was writing in 150 B.C.nSimilarly, modern “internationalsystemsntheory,” so much more sophisticatednand intellectually impressiventhan any metrocentric theory ofn”imperialism,” has its origins in thenwork of Jacqueline de Romilly—worknon the thought of Thucydides (whonwrote ca. 400 B.C.). Thucydides attributednthe rise and fall of Athens tondifferential power within an anarchicninternational system.nWhat enabled these ancient Greeknpolitical scientists to see the great complexitiesnof international relations withnsuch clear eyes and to write with suchnanalytical dispassion? We can always,nof course, take refuge in such ideas asn”the genius of ancient Greece.” Butnwe would be better off looking insteadnat ourselves. At least part of the answernhere is that these ancient thinkers,nwhen analyzing the expansion ofnstates, were able to work unencumberednby the corrupt modern history ofnterms such as “imperialism.” (Doyle,nincidentally, blandly and briefly definesn”imperialism” as “the actualnprocess by which empires are gainednand maintained”—and then drops thenterm.) And it says a good deal aboutnour century and its intellectual historynthat here at the end of it we are at last,nand after great effort and turmoil,nstruggling to reach a level of sophisticationnconcerning the analysis of empirenthat was originally achieved morenthan 2,000 years ago.nNOVEMBER 1987135n