The Sin of Speaking.

From The Life of Thaddeus Stevens, by James Albert Woodburn, p. 103:

The sum total of anti-slavery sinning was in the failure to keep silence.

Woodburn wrote that comparing the anti-slavery speeches given by Thad Stevens and Horace Mann in the House in February 1850.

Mann was gentle, eloquent, "refined and scholarly," whereas Stevens spared no feelings, minced no words, deferred to none. Stevens returned the rhetoric of the Southern fire-eaters bit by bit, and the Southern response was to claim woundedness, hurt feelings. In the words of the 11 March 1850 speech of Stanly, a representative from North Carolina:

I hope his next speech will be fit to read in the families of Pennsylvania farmers,. . . [and that] the gentleman will find some other Morgan to frighten the grandmothers and children of Pennsylvania with. I ask him to let us alone.

Emphasis added.

The point is that when the Southerners were challenged, whether in gentler terms by Mann or in more forceful and equal terms by Stevens, they threw up their hands and retreated to a position of, "Leave us alone!" Of course, the Southern representatives were vigorous in their opposition to admitting new territories as free states, vigorous in their dire warnings of impending disunion if Northerners dared to disrespect Southern slavery. The "leave us alone" trope obviously connects with the plea of states' rights.

Thus the power of speaking in the face of silence. A lesson we still have yet to fully learn.