formidable　increase　of　the　power　of　another　state　（potestas
  tremenda）　by　acquisition　of　territory。　Lesion　of　a　less　powerful
  country　may　be　involved　merely　in　the　condition　of　a　more　powerful
  neighbour　prior　to　any　action　at　all；　and　in　the　state　of　nature　an
  attack　under　such　circumstances　would　be　warrantable。　This
  international　relation　is　the　foundation　of　the　right　of
  equilibrium；　or　of　the　〃balance　of　power；〃　among　all　the　states　that
  are　in　active　contiguity　to　each　other。
  The　right　to　go　to　war　is　constituted　by　any　overt　act　of　injury。
  This　includes　any　arbitrary　retaliation　or　act　of　reprisal
  （retorsio）　as　a　satisfaction　taken　by　one　people　for　an　offence
  committed　by　another；　without　any　attempt　being　made　to　obtain
  reparation　in　a　peaceful　way。　Such　an　act　of　retaliation　would　be
  similar　in　kind　to　an　outbreak　of　hostilities　without　a　previous
  declaration　of　war。　For　if　there　is　to　be　any　right　at　all　during
  the　state　of　war；　something　analogous　to　a　contract　must　be　assumed；
  involving　acceptance　on　the　side　of　the　declaration　on　the　other；
  and　amounting　to　the　fact　that　they　both　will　to　seek　their　right　in
  this　way。
  57。　Right　during　War。
  The　determination　of　what　constitutes　right　in　war；　is　the　most
  difficult　problem　of　the　right　of　nations　and　international　law。　It　is
  very　difficult　even　to　form　a　conception　of　such　a　right；　or　to
  think　of　any　law　in　this　lawless　state　without　falling　into　a
  contradiction。　Inter　arma　silent　leges。*　It　must　then　be　just　the
  right　to　carry　on　war　according　to　such　principles　as　render　it　always
  still　possible　to　pass　out　of　that　natural　condition　of　the　states
  in　their　external　relations　to　each　other；　and　to　enter　into　a
  condition　of　right。
  *＇〃In　the　midst　of　arms　the　laws　are　silent。〃　Cicero。＇
  No　war　of　independent　states　against　each　other　can　rightly　be　a　war
  of　punishment　（bellum　punitivum）。　For　punishment　is　only　in　place
  under　the　relation　of　a　superior　（imperantis）　to　a　subject　（subditum）；
  and　this　is　not　the　relation　of　the　states　to　one　another。　Neither　can
  an　international　war　be　〃a　war　of　extermination〃　（bellum
  internicinum）；　nor　even　〃a　war　of　subjugation〃　（bellum　subjugatorium）；
  for　this　would　issue　in　the　moral　extinction　of　a　state　by　its
  people　being　either　fused　into　one　mass　with　the　conquering　state；
  or　being　reduced　to　slavery。　Not　that　this　necessary　means　of
  attaining　to　a　condition　of　peace　is　itself　contradictory　to　the　right
  of　a　state；　but　because　the　idea　of　the　right　of　nations　includes
  merely　the　conception　of　an　antagonism　that　is　in　accordance　with
  principles　of　external　freedom；　in　order　that　the　state　may　maintain
  what　is　properly　its　own；　but　not　that　it　may　acquire　a　condition
  which；　from　the　aggrandizement　of　its　power；　might　become
  threatening　to　other　states。
  Defensive　measures　and　means　of　all　kinds　are　allowable　to　a　state
  that　is　forced　to　war；　except　such　as　by　their　use　would　make　the
  subjects　using　them　unfit　to　be　citizens；　for　the　state　would　thus
  make　itself　unfit　to　be　regarded　as　a　person　capable　of
  participating　in　equal　rights　in　the　international　relations　according
  to　the　right　of　nations。　Among　these　forbidden　means　are　to　be
  reckoned　the　appointment　of　subjects　to　act　as　spies；　or　engaging
  subjects　or　even　strangers　to　act　as　assassins；　or　poisoners　（in　which
  class　might　well　be　included　the　so　called　sharpshooters　who　lurk　in
  ambush　for　individuals）；　or　even　employing　agents　to　spread　false
  news。　In　a　word；　it　is　forbidden　to　use　any　such　malignant　and
  perfidious　means　as　would　destroy　the　confidence　which　would　be
  requisite　to　establish　a　lasting　peace　thereafter。
  It　is　permissible　in　war　to　impose　exactions　and　contributions
  upon　a　conquered　enemy；　but　it　is　not　legitimate　to　plunder　the　people
  in　the　way　of　forcibly　depriving　individuals　of　their　property。　For
  this　would　be　robbery；　seeing　it　was　not　the　conquered　people　but
  the　state　under　whose　government　they　were　placed　that　carried　on
  the　war　by　means　of　them。　All　exactions　should　be　raised　by　regular
  requisition；　and　receipts　ought　to　be　given　for　them；　in　order　that
  when　peace　is　restored　the　burden　imposed　on　the　country　or　the
  province　may　be　proportionately　borne。
  58。　Right　after　War。
  The　right　that　follows　after　war；　begins　at　the　moment　of　the　treaty
  of　peace　and　refers　to　the　consequences　of　the　war。　The　conqueror　lays
  down　the　conditions　under　which　he　will　agree　with　the　conquered　power
  to　form　the　conclusion　of　peace。　Treaties　are　drawn　up；　not　indeed
  according　to　any　right　that　it　pertains　to　him　to　protect；　on
  account　of　an　alleged　lesion　by　his　opponent；　but　as　taking　this
  question　upon　himself；　he　bases　the　right　to　decide　it　upon　his　own
  power。　Hence　the　conqueror　may　not　demand　restitution　of　the　cost　of
  the　war；　because　he　would　then　have　to　declare　the　war　of　his　opponent
  to　be　unjust。　And　even　although　he　should　adopt　such　an　argument；　he
  is　not　entitled　to　apply　it；　because　he　would　have　to　declare　the
  war　to　be　punitive；　and　he　would　thus　in　turn　inflict　an　injury。　To
  this　right　belongs　also　the　exchange　of　prisoners；　which　is　to　be
  carried　out　without　ransom　and　without　regard　to　equality　of　numbers。
  Neither　the　conquered　state　nor　its　subjects　lose　their　political
  liberty　by　conquest　of　the　country；　so　as　that　the　former　should　be
  degraded　to　a　colony；　or　the　latter　to　slaves；　for　otherwise　it
  would　have　been　a　penal　war；　which　is　contradictory　in　itself。　A
  colony　or　a　province　is　constituted　by　a　people　which　has　its　own
  constitution；　legislation；　and　territory；　where　persons　belonging　to
  another　state　are　merely　strangers；　but　which　is　nevertheless
  subject　to　the　supreme　executive　power　of　another　state。　This　other
  state　is　called　the　mother…country。　It　is　ruled　as　a　daughter；　but　has
  at　the　same　time　its　own　form　of　government；　as　in　a　separate
  parliament　under　the　presidency　of　a　viceroy　（civitas　hybrida）。　Such
  was　Athens　in　relation　to　different　islands；　and　such　is　at　present
  （1796）　the　relation　of　Great　Britain　to　Ireland。
  Still　less　can　slavery　be　deduced　as　a　rightful　institution；　from
  the　conquest　of　a　people　in　war；　for　this　would　assume　that　the　war
  was　of　a　punitive　nature。　And　least　of　all　can　a　basis　be　found　in　war
  for　a　hereditary　slavery；　which　is　absurd　in　itself；　since　guilt
  cannot　be　inherited　from　the　criminality　of　another。
  Further；　that　an　amnesty　is　involved　in　the　conclusion　of　a　treaty
  of　peace　is　already　implied　in　the　very　idea　of　a　peace。
  59。　The　Rights　of　Peace。
  The　rights　of　peace　are：
  1。　The　right　to　be　in　peace　when　war　is　in　the　neighbourhood；　or　the
  right　of　neutrality。
  2。　The　right　to　have　peace　secured　so　that　it　may　continue　when　it
  has　been　concluded；　that　is；　the　right　of　guarantee。
  3。　The　right　of　the　several　states　to　enter　into　a　mutual
  alliance；　so　as　to　defend　themselves　in　common　against　all　external　or
  even　internal　attacks。　This　right　of　federation；　however；　does　not
  extend　to　the　formation　of　any　league　for　external　aggression　or
  internal　aggrandizement。
  60。　Right　as　against　an　Unjust　Enemy。
  The　right　of　a　state　against　an　unjust　enemy　has　no　limits；　at　least
  in　respect　of　quality　as　distinguished　from　quantity　or　degree。　In
  other　words；　the　injured　state　may　use…　not；　indeed　any　means；　but
  yet…　all　those　means　that　are　permissible　and　in　reasonable　measure　in
  so　far　as　they　are　in　its　power；　in　order　to　assert　its　right　to
  what　is　its　own。　But　what　then　is　an　unjust　enemy　according　to　the
  conceptions　of　the　right　of　nations；　when；　as　holds　generally　of　the
  state　of　nature；　every　state　is　judge　in　its　own　cause？　It　is　one
  whose　publicly　expressed　will；　whether　in　word　or　deed；　betrays　a
  maxim　which；　if　it　were　taken　as　a　universal　rule；　would　make　a
  state　of　peace　among　the　nations　impossible；　and　would　necessarily
  perpetuate　the　state　of　nature。　Such　is　the　violation　of　public
  treaties；　with　regard　to　which　it　may　be　assumed　that　any　such
  violation　concerns　all　nations　by　threatening　their　freedom；　and
  that　they　are　thus　summoned　to　unite　against　such　a　wrong　and　to
  take　away　the　power　of　committing　it。　But　this　does　not　include　the
  right　to　partition　and　appropriate　the　country；　so　as　to　make　a
  state　as　it　were　disappear　from　the　earth；　for　this　would　be　an
  injustice　to　the　people　of　that　state；　who　cannot　lose　their
  original　right　to　unite　into　a　commonwealth；　and　to　adopt　such　a　new
  constitution　as　by　its　nature　would　be　unfavourable　to　the　inclination
  for　war。
  Further；　it　may　be　said　that　the　expression　〃an　unjust　enemy　in
  the　state　of　nature〃　is　pleonastic；　for　the　state　of　nature　is
  itself　a　state　of　injustice。　A　just　enemy　would　be　one　to　whom　I　would
  do　wrong　in　offering　resistance；　but　such　a　one　would　really　not　be　my
  enemy。
  61。