Judge Ketanji Brown Jackson, who President Biden nominated to the Supreme Court to become the first ever Black female justice, admitted Tuesday that she could not recall the basis for the infamous Dred Scott decision, which in 1857 said that a Black person whose ancestors had been slaves could not be an American citizen.

The case came up during Jackson’s confirmation hearing on Tuesday, when she faced questioning from Sen. John Cornyn, R-Texas. Cornyn brought up the concept of substantive due process, a legal doctrine utilized to expand the Constitution’s due process clause to protect various rights not enumerated in the Constitution.

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"Why isn't substantive due process just another way for judges to hide their policy making under the guise of interpreting the Constitution," Cornyn said, criticizing the doctrine.

Supreme Court nominee Ketanji Brown Jackson testifies during her Senate Judiciary Committee confirmation hearing on Capitol Hill in Washington, Tuesday, March 22, 2022. (AP Photo/Andrew Harnik)

Supreme Court nominee Ketanji Brown Jackson testifies during her Senate Judiciary Committee confirmation hearing on Capitol Hill in Washington, Tuesday, March 22, 2022. (AP Photo/Andrew Harnik)

Earlier, Cornyn referenced the Scott case as having been cited as "a product of substantive due process." The case was brought by Dred Scott, a slave who left Missouri and went to Illinois, where slavery was illegal. Upon returning to Missouri, Scott sued claiming that he had been freed by moving to a state where he could not be a slave. The Supreme Court ruled against him, stating that he did not have standing to bring the case in the first place, but also that allowing Scott to be free would deprive his owner of property – Scott himself – without due process.

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Responding to Cornyn’s question about substantive due process, Jackson described the doctrine itself, noting that justices "have interpreted that to mean not just procedural rights relative to government action, but also the protection of certain personal rights related to intimacy and autonomy."

Sen. John Cornyn, R-Texas, questions Supreme Court nominee Ketanji Brown Jackson during a Senate Judiciary Committee confirmation hearing on Capitol Hill in Washington, Tuesday, March 22, 2022. (AP Photo/Andrew Harnik)

Sen. John Cornyn, R-Texas, questions Supreme Court nominee Ketanji Brown Jackson during a Senate Judiciary Committee confirmation hearing on Capitol Hill in Washington, Tuesday, March 22, 2022. (AP Photo/Andrew Harnik)

Jackson noted that this has included rights to rear children, travel, marry, marry a different race, get an abortion and use contraception.

"Treating slaves as chattel property," Cornyn interjected, citing the Scott case.

"I don't quite remember the basis for the Dred Scott opinion," Jackson said, stating that she trusted Cornyn’s take on it.

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While substantive due process was the basis for the court’s reasoning that they could not deprive a slave owner of property by deeming the slave to be free, the basis of the decision was that even former slaves could not sue in federal court because they could not be U.S. citizens.

The Scott case was effectively nullified with the ratification of the Fourteenth Amendment, which stated that all people born or naturalized in the U.S. are citizens.