A group of White House counsel Pat Cipollone’s former law school classmates has taken aim at his letter detailing the Trump administration’s refusal to cooperate with House Democrats’ impeachment inquiry.

In an Oct. 10 letter, 21 members of the University of Chicago Law School class of 1991 urged Cipollone to “retract” the letter he sent to congressional Democrats earlier in the week, in which he wrote that President Donald Trump rejects the “constitutionally defective” House impeachment inquiry.