In a move that may be a first of its kind, Sen. Cory Booker, D-N.J., will testify against fellow Sen. Jeff Sessions when the Alabama Republican appears before the Senate Judiciary Committee.

Booker said he does not "take the decision lightly" to testify on Wednesday. Yet President-elect Donald Trump's attorney general nominee has too many problematic policy stances and a record that is in his view "deeply troubling."

"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 common sense, bipartisan immigration reform," a statement from Booker's office released Monday night reads.

This may be the first time a sitting senator has testified against a colleague during a confirmation hearing.

Booker added that he "lack[s] the confidence" that as attorney general, Sessions can ensure "the fair administration of justice."

Booker will be joined by two other prominent African-American lawmakers in testifying against Sessions, Rep., John Lewis, D-Ga., and Rep Cedric Richmond, D-La.

Sessions' nomination to be the next attorney general has been met with the most criticism of any of Trump's cabinet nominees. However, Republicans have a 52-seat majority and need only a majority vote to clear Sessions past the upper chamber.

Roughly 30 years ago, Sessions' nomination to be a federal judge sank after allegations of racism.

Republicans this time are not willing to cede that contentious ground without a fight. Committee members have added prominent African-American supporters to argue for Sessions.

These new pro-Sessions witnesses include former assistant federal attorney Willie Huntley, former Federal Marshal Jesse Seroyer, and former chief counsel to a senate subcommittee Will Smith.

Susan Crabtree contributed to this report.