Sen. Cory Booker will on Wednesday take the apparently unprecedented step of testifying against the confirmation of fellow Sen. Jeff Sessions of Alabama to be attorney general, a move that could firm up Booker’s progressive bona fides ahead of a possible 2020 presidential bid.



“I do not take lightly the decision to testify against a Senate colleague,” Booker, a New Jersey Democrat, said in a statement. “But the immense powers of the attorney general, combined with the deeply troubling views of this nominee is a call to conscience.”

[Democrats to Grill Sessions on Race, Civil Rights]

“Sen. Sessions’ decades-long record is concerning in a number of ways, from his opposition to bipartisan criminal justice reform to his views on bipartisan drug policy reform, from his efforts earlier in his career to deny citizens voting rights to his criticism of the Voting Rights Act, from his failure to defend the civil rights of women, minorities, and LGBT Americans to his opposition to commonsense, bipartisan immigration reform,” said Booker, who is African-American.

Booker’s office told Roll Call that the Senate Historical Office could find no precedent for a senator testifying against a sitting colleague at a confirmation hearing.