Even though the US added new territory only 37 years ago (pop quiz!), in a very real sense the borders of the country have only changed in minor ways in 170 years, the formal structure of the government has changed little in that same time, and the wars and revolutions of the 20th century were visited on the inhabitants of the US hardly at all. So the American belief in the immutability of the world-system etc, which is definitely real, also has a fairly strong basis for Americans.
Even though the US added new territory only 37 years ago (pop quiz!), in a very real sense the borders of the country have only changed in minor ways in 170 years, the formal structure of the government has changed little in that same time, and the wars and revolutions of the 20th century were visited on the inhabitants of the US hardly at all. So the American belief in the immutability of the world-system etc, which is definitely real, also has a fairly strong basis for Americans.