William Alexander MacCorkle was the son of a Confederate Major, and the ninth Governor of the state of West Virginia, a state which had been created in 1863 and where it has been said "the Scotch-Irish were unmatched. No other ethnic group would be as significant in shaping the culture of West Virginia.” (from this previous post).
The MacCorkles came from Ulster, and traced their Scottish origins to the Highlands. Initially a William MacCorkle settled at Rockbridge County in Virginia in the 1730s. The famous Revolutionary hero Patrick Henry appointed a John MacCorkle as Ensign in the Rockbridge Militia in the 1770s. Various generations of the family were elders in Presbyterian congregations; an Emmett W McCorkle attended the Pan-Presbyterian Council, visited Britain a few times, and wrote a volume entitled The Scotch-Irish in Virginia. By the time the Civil War of 1861–65 came around, there were 200 MacCorkles in the Confederate ranks, and they were one of the biggest families in Rockbridge.
William Alexander MacCorkle took office in 1893, nearly 30 years after the Civil War was over. Yet ‘carpetbaggers’ has stripped the South in the aftermath of the war, and in MacCorkle’s inaugural speech he pulled no punches:
The State is rapidly passing under the control of large foreign and non-resident land owners. We welcome into our State the immigrant who comes to us with the idea of home seeking and home building with all its profits to the State, with its family ties, with its clearing of the forests, its building of church and school house, its expenditure of all that is made in our State, and its exercise of citizenship. But the men who today are purchasing the immense areas of the most valuable lands in the State, are not citizens and have only purchased in order that they may carry to their distant homes in the North, the usufruct of the lands of West Virginia, thus depleting the State of its wealth to build grandeur and splendor in other States. In a few years at the present rate of progress, we will occupy the same position of vassalage to the North and East that Ireland does to England, and to some extent, for the same reasons.
In this 1908 address, given at Washington and Lee University in Lexington, he traced the valiant men of the South right back to Knox and Calvin, and had this to say:
One more persistent, more earnest, and who exerted a greater influence upon Southern life in the actual struggle for liberty than the Cavalier, was the Scotch Covenanter, the Scotch-Irishman of this day and place … the populations of the colonies of the South were largely homogenous, and after the great Scotch-Irish immigration and the German immigration there was practically no immigration into the South. Men from the South who fought in the War of 1812 and the Mexican War and the War of 1860 were the sons and grandsons of the men who carried arms in the Revolution of 1776.
There are lots of other usages of the term Scotch-Irish in that same address. These American writers of the past had little or no cultural advantage in citing Scotch-Irishness. They referenced it because it was true.