Merrow (1991) claims that alliances can shift because of changes in th
e policy preferences of the regimes that control states. This is count
er to the central theoretical position of neorealist theory that sees
alliances as the outgrowth of particular distributions of power in an
anarchic international system. Drawing on regime changes in Europe bet
ween 1816 and 1965, we evaluate the relative merits of these contradic
tory claims. Our data support the conclusion that regime changes that
were (I) externally imposed, (2) the result of internal revolution, or
(3) nonviolent, but occurred in the context of an internal political
crisis; all had significant effects on a state's restructuring of its
alliances, even when other variables, such as changes in the distribut
ion of power and the state's power status, are held constant.