They saw all the consequences in the principle, and they avoided the consequences by denying the principle.

Via Ann Althouse

An interesting citation of James Madison in his letter To the Honorable the General Assembly of the Commonwealth of Virginia A Memorial and Remonstrance, 20 June 1785, Papers 8:298--304.

The sophistication and clarity of thought of these Founding Fathers is almost incomprehensible. The wisdom of these giants in comparison to the moral and intellectual political pygmies of today is a continuing rebuke to our political class.

Because it is proper to take alarm at the first experiment on our liberties. We hold this prudent jealousy to be the first duty of Citizens, and one of the noblest characteristics of the late Revolution. The free men 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. We revere this lesson too much soon to forget it.

Madison was speaking in the context of religion but the threat of gradual, well intentioned encroachment is real and ever present.

Pragmatists usually attempt to warrant an encroachment based on how miniscule is the nature of the assessment. Madison calls us back to answer the question of principle instead of focusing on practicality. It doesn't matter if the tactical cost is small if the strategic cost (of loss of freedom) is huge.

Who does not see that the same authority which can establish Christianity, in exclusion of all other Religions, may establish with the same ease any particular sect of Christians, in exclusion of all other Sects? that the same authority which can force a citizen to contribute three pence only of his property for the support of any one establishment, may force him to conform to any other establishment in all cases whatsoever?