"most important piece or feature," 1831, from French pièce de résistance, originally "the most substantial dish in a meal." Literally "piece of resistance;" there seems to be disagreement as to the exact signification.
coined 1866 by Thoreau as the title of his essay originally published (1849) as "Resistance to Civil Government."
If the alternative is to keep all just men in prison, or give up war and slavery, the State will not hesitate which to choose. If a thousand men were not to pay their tax-bills this year, that would not be a violent and bloody measure, as it would be to pay them, and enable the State to commit violence and shed innocent blood. This is, in fact, the definition of a peaceable revolution, if any such is possible. [Thoreau]