Natural Morality, American Exceptionalism, and Race Relations by S. Adam Seagrave.
The anti-slavery arguments of American abolitionists demonstrate the way in which Lockean natural rights and Thomistic natural law can be reconciled.
When considering the most significant and influential concepts in American political thought and history, Thomistic natural law does not readily spring to mind. While the idea of natural law does appear on the landscape in a couple of crucial places—Jefferson’s reference to the “laws of nature” in the Declaration of Independence and Martin Luther King, Jr.’s discussion of the “moral law” in his “Letter from a Birmingham Jail” among them—this idea always seems, when viewed from the broad perspective of the history of American political thought, to be playing a cameo rather than a starring role. This may be partly due to the fact that the much more central American idea of individual natural rights is often perceived to be in serious tension with Thomistic natural law—the former emphasizes the individual while the latter emphasizes the community.
It may come as a surprise, then, to notice that the defining intellectual moment of American political thought and history—our struggle with race-based slavery—was, in fact, premised largely upon an implicit marriage between the idea of individual natural rights and Thomistic natural law. As Frederick Douglass had hoped, America became “exceptional” by overcoming its uniquely egregious moral failures, and in doing so advanced an idea of natural morality that went beyond both “ancients” and “moderns.”