President Trump is considering pardoning family members and staffers caught up in the Russia investigation, but legal experts warn that it could backfire by making it harder for them to avoid testifying.

Under the Fifth Amendment to the Constitution, Americans are protected against self-incrimination, but people who have been pardoned are no longer under any legal jeopardy, Harvard Law School Professor Laurence Tribe told TIME.

“Anyone pardoned by Trump would lose most of the 5th Amendment’s protection against compelled testimony that might otherwise have incriminated the pardoned family member or associate, making it much easier for DOJ and Congress to require such individuals to give testimony that could prove highly incriminating to Trump himself,” Tribe said in an email.

Still, that could lead to another constitutional standoff, if the recipients of the Trump pardons refused to testify before Congress. Mark Osler, a University of St. Thomas Law School professor who has written about the president’s pardon powers, said Congress might respond by holding them in contempt, leading to a second pardon.