The political concept is Militarism:
Militarism is the belief or the desire of a government or a people
that a state should maintain a strong military capability to use it
aggressively to expand or promote national interests; examples of
militarist states include the United States, Russia and France.1 It
may also imply the glorification of the military and of the ideals of
a professional military class and the "predominance of the armed
forces in the administration or policy of the state"2 (see also:
stratocracy and military junta).
However a word that is commonly used in political argumentation is warmongering (also).
This term is widely used both in politics, and specially in propaganda. Labeling a country with it, thought, is simplistic. It does not reflect its citizens, its context, and its history. There might be relevance to such opinion but I don't think comparing the US with Orwell 1984 is the way to go (although the "unite against common enemy" is a common social mechanism used in politics).
If you really wan't to understand the historical circumstances behind the views you seem to hinting at you should start by analyzing Einsenhower's farewell address (emphasis is mine):
...was the final public speech of Dwight D. Eisenhower as the 34th
President of the United States, delivered in a television broadcast on
January 17, 1961. Perhaps best known for advocating that the nation
guard against the potential influence of the military–industrial
complex, a term he is credited with coining, the speech also expressed
concerns about planning for the future and the dangers of massive
spending, especially deficit spending, the prospect of the domination
of science through Federal funding and, conversely, the domination of
science-based public policy by what he called a
As for this so called Military-Industrial complex you also have a nice article in wikipedia:
The military–industrial complex (MIC) is an informal alliance between
a nation's military and the arms industry which supplies it, seen
together as a vested interest which influences public
policy.13 A driving factor behind this relationship between
the government and defense-minded corporations is that both sides
benefit—one side from obtaining war weapons, and the other from being
paid to supply them.5 The term is most often used in reference to
the system behind the military of the United States, where it is most
prevalent6 and gained popularity after its use in the farewell
address of President Dwight D. Eisenhower on January 17, 1961.7
In 2011, the United States spent more (in absolute numbers) on its
military than the next 13 nations combined.
I'm not arguing that this is an accurate/full explanation for the phenomena you are asking about but it certainly seems more reasonable than to believe in a nationwide ingrained behavior for warmongering.
EDIT: another expression (mostly informal) that has been used in political context is Gunboat Diplomacy:
In international politics, gunboat diplomacy (or "Big Stick
ideology" in U.S. history) refers to the pursuit of foreign policy
objectives with the aid of conspicuous displays of naval power –
implying or constituting a direct threat of warfare, should terms not
be agreeable to the superior force.