Scholars and observers of the international system often comment on the dec
reasing importance of international boundaries as a result of the growth of
international economic and social exchanges, economic liberalization, and
international regimes. They generally fail to note, however, that coercive
territorial revisionism has markedly declined over the past half century-a
phenomenon that indicates that in certain ways states attach greater import
ance to boundaries in our present era. In this article I first trace states
' beliefs and practices concerning the use of force to alter boundaries fro
m the birth of the Westphalian order in the seventeenth century through the
end of World War II. I then focus on the increasing acceptance of the norm
against coercive territorial revisionism since 1945. Finally, I analyze th
ose instrumental and ideational factors that have influenced the strengthen
ing of the norm among both Western and developing countries.