The passage below is from Federalist 51, written by James Madison in 1788.
"...the Interior structure of the government as that its several constituent parts may, by their mutual relations, be the means of keeping each other in their proper places."
Which constitutional principle does Madison describe in the passage?

A. popular sovereignty
B. Judicial review
C checks and balances
D. separation of powers

What was one reason that southern states passed laws after 1800 to discourage manumission? 1)southern whites feared that freed blacks would seek revenge for past treatment as slaves. 2) northern leaders pressured southerners to liberate enslaved people. 3)southern states needed an inexpensive labor force to work in southern factories. 4)northern whites had sold their slaves to southerners before slavery was banned in the north.