In its history the United States has gone through many different eras each with its own policy. During the era of expansion the policy was one of cleaning house and starting over in the top levels of government. It was also the policy to try and expand the young country's land mass.
containment
NorthWest Ordinance
so they can trade more and get more policy power
the industrial revolution
Then the US would have been the aggresser. That is NOT our policy.
Japan took part in the World War while America was in its expansion era
Growth of the railroads
During the 19th century expansion era of the United States, Alaska was essentially ignored. Too much land and resources were available in the lower 48 to bother with the harsh conditions that far north.
laissez-faire
containment
President Harry S. Truman created the Truman Doctrine which called for the policy of containment during the Cold War era.
It became property of the United States.
the Vietnam war
Containment
== ==
NorthWest Ordinance
so they can trade more and get more policy power