All of the secessionist activity was motivated by fear for the institution of slavery in the South. If the President (and, by extension, the appointed federal officials in the South, such as district attorneys, marshals, postmasters, and judges) opposed slavery, it might collapse. There were fears that abolitionist agents would infiltrate the South and foment slave insurrections. (The noted secessionist William Lowndes Yancey, speaking at New York's Cooper Institute in October 1860, asserted that with abolitionists in power, "Emissaries will percolate between master [and] slave as water between the crevices of rocks underground. They will be found everywhere, with strychnine to put in our wells.") Less radical Southerners thought that with Northern antislavery dominance of the federal government, slavery would eventually be abolished, regardless of present constitutional limits.