Why is Oceania always in a war? Whats the point of changing opponents so frequently?

In
chapter nine of part two,begins to read 's book entitled The Theory and Practice of
Oligarchical Collectivism from the comfort of his rented apartment above Mr.
Charrington's antique shop. Winston reads about the meaning of the Party's slogan "War is
Peace" and recognizes that the government uses war as a tool to oppress and control the
populace. Unlike in the wars of the past, Oceania does not seek to conquer new territories or
even destroy other nations, because it would be impossible. Instead, Oceania is engaged in a
continuous war in order to exhaust its industrial resources and purposely keep the standard of
living low. Essentially, continuous warfare is the only way to continue producing goods without
increasing the wealth and power of the masses or compromising the nation's industrial strength.
Continuous warfare also creates a hysterical environment, which keeps the population suppressed
while simultaneously bolstering support for the Party. There is actually no point to changing
enemies so frequently, butuses it as a way to emphasize the power of "doublethink" and
the Party's influence on independent thought.