Outgoing Sen. Jeff Flake (R-AZ) on Sunday expressed frustration that his bill to protect special counsel Robert Mueller’s investigation isn’t seen “as a priority” by his colleagues.

“How in the world my colleagues don’t see this as a priority now I just don’t understand,” Flake said on CNN’s “State of the Union.”

The senator stuck by his threat to block Trump administration judicial nominees until the bill is brought to the Senate floor for a vote.

“It does need to come to the Senate floor, and I think it’s worth using a little leverage here,” Flake said.