No law is stronger than is the public sentiment where it is to be enforced.

Abraham Lincoln (1809-1865) American lawyer, politician, US President (1861-65)

Letter (1859-12-22) to John J. Crittenden
    (Source)

Crittenden was a US Senator from Kentucky, a former Whig but at the time part of the American (Know-Nothing) Party. Lincoln was criticizing the idea of a party platform with the sole position of "The Constitution, the Union, and the enforcement of the laws," and used the resistance to the Fugitive Slave Act in the North as an example.

See Lincoln (1858).