“Four of Calhoun’s ideas are especially relevant today. The first is that patriotism doesn’t spring from high ideals, but from citizens and the state having a mutual stake in each other’s success. Calhoun’s second main argument is that America’s racially discriminatory policies, including slavery, unify white citizens, protect democracy, and mitigate class differences. Calhoun’s third argument opposed admitting non-whites as citizens of the Union and the pursuit of empire. Finally, Calhoun’s most consequential ideal is that of the concurrent majority. This, presented in A Disquisition on Government and in a Discourse on the Constitution and Government of the United States, is probably the most significant American contribution to serious political science since The Federalist.”
Regardless if you do not lean to the Hard Right or not, I highly recommend the new biography of Calhoun entitled Calhoun: American Heretic.
As the author states, it is a unintentional glance into national decline, but more importantly, it describes the historical reasons for that decline in exacting detail.