Slippery Slope Arguments in History: James Madison
Camel (A) sticks his nose under the tent (B), which collapses, driving the thin end of the wedge (C) to cause monkey to open floodgates (D), letting water flow down the slippery slope (E) to irrigate acorn (F) which grows into oak (G). [Illustration by Eric Kim, from my idea.]
From Madison's Remonstrance Against Religious Assessments (1786):
[I]t is proper to take alarm at the first experiment on our liberties. The freemen of America did not wait till usurped power had strengthened itself by exercise, and entangled the question in precedents. They saw all the consequences in the principle, and they avoided the consequences by denying the principle.