Jefferson never freed most of his slaves, and he remained silent on the issue while he was president.[392][403] Contextualists such as Joseph J. Ellis emphasize a change in Jefferson's thinking from his emancipationist views before 1783, noting Jefferson's shift toward public passivity and procrastination on policy issues related to slavery. Jefferson seemed to yield to public opinion by 1794 as he laid the groundwork for his first presidential campaign against Adams in 1796.[404]
Historian Henry Wiencek said Jefferson "rationalized an abomination to the point where an absolute moral reversal was reached and he made slavery fit into America's national enterprise."[405]

Jefferson–Hemings controversy
Main article: Jefferson–Hemings controversy
See also: Sally Hemings
Jefferson depicted as a rooster, and Hemings as a hen
Claims that Jefferson fathered Sally Hemings's children have been debated since 1802. That year James T. Callender, after being denied a position as postmaster, alleged Jefferson had taken Hemings as a concubine and fathered several children with her.[406] In 1998, a panel of researchers conducted a Y-DNA study of living descendants of Jefferson's uncle, Field, and of a descendant of Hemings's son, Eston Hemings. 