When one considers the role of race and racism in Southern life and the settlement and conquest of the U.S. west, was the pursuit of empire in 1898 really such a departure from U.S. political traditions – or did leaving American shores mark a real change?

Race and racism were fundamental elements in the founding of the United States. A race-based form of chattel slavery was instituted before the government declared itself independent from Great Britain, and continued to be the economic base of the new nation for almost another one hundred years. This system used racial categories as a means to dehumanize people in order to make it acceptable to keep rights reserved for certain racial classes. The slow genocide perpetrated against Native Americans by white settlers also showed the willingness of Americans to use race as an excuse to remove people seen as racial "others" from their lands, using force when necessary. The concept of Manifest Destiny, itself a racist policy that promoted the supremacy of white Christians, is a direct precursor to the types of imperial policies pursued at the end of the 19th and beginning of the 20th Centuries. Once the continent had been conquered, from sea to shining sea, the logical next move for a growing nation was to spread itself across the seas. Sentiments like those expressed in Rudyard Kipling's poem "White Man's Burden" express the racist ideas commonly accepted and promoted by elected officials of the era and their policies often reflected this, especially in island nations like the Philippines and Cuba.

This is a great question. Racism, through the genocide of indigenous people of what is now known as the US, and the enslavement of African peoples, was absolutely foundational to the creation of America. The foundation of the United State's economy was built on slavery and US domestic expansion was made through genocide. So, certainly, America's change from isolationism to interventionism and imperialism abroad is absolutely not a surprising development. For, one must remember, it was the initial imperialism by the European settlers of indigenous people that led to the creation of the United States. When the United States's military gained control of Guam, the Philippines, and Puerto Rico, the same racist policies that had been exercised domestically translated to global racism and imperialism.