Iraq and Barbary Pirates

If you read the essay, by Robert Kagan, entitled "Power and Weakness" one could get the sense that the application of military force to settle a far flung conflict or threat of conflict was unused prior to the 20th century. Until the U.S. had enough power to exert itself.

While I agree with this mostly, I do think it ignores some facts. Namely our very early conflict with the Barbary Pirates. Here is a paper entitled "America and the Barbary Pirates: An International Battle Against an Unconventional Foe", by Gerard W. Gawalt, that talks about out very early conflict with the Barbary Pirates. Here is another article Terrorism In Early America,The U.S. Wages War Against The Barbary States To End International Blackmail and Terrorism, by Thomas Jewett.

The point is that the U.S. has been willing in the 18th and 19th centuries to wage war, regardless iof it's power structure, assumming the adversary was not a super-power itself. This is even more true if you consider our relentless expansion into Indian territory as an excercise in power against sovereign nations.