Democrats vowing to investigate President Donald Trump’s commutation of Roger Stone’s prison sentence will face significant constitutional hurdles, especially after a Supreme Court ruling on the limits of congressional subpoenas, according to former House lawyers.

House Judiciary Committee Chair Jerry Nadler and House Oversight Committee Chair Carolyn Maloney said in a joint statement after Stone’s commutation that they want White House counsel Pat Cipollone to brief them on the grant of clemency. Nadler added that his committee “will conduct an aggressive investigation into this brazen corruption.”