He differentiates between them insofar that he supported the War of 1812 since he believed that it was about protecting American ideals and the United States from Britain. He, however, didn't have support for the Mexican war because he feared that taking Texas would cause slavery issue to rise and create problems for the union.
The governments of Saudi Arabia and the United States are different because the United States is considered a democracy and Saudi Arabia is a autocracy or dictatorship.
The most important role of the Parthians in the Silk Road trade was their ability to provide Chinese silk to the Romans, who had a seemingly endless appetite for this material.
