Sen. Jeff Flake (R-Ariz.) is going out with a bang. He announced today that he will oppose all of President Trump’s judicial nominations until legislation protecting special counsel Robert Mueller gets a vote.

“I have informed the majority leader I will not vote to advance any of the 21 judicial nominees pending in the Judiciary Committee or vote to confirm the 32 judges awaiting confirmation on the Senate floor until … [the bill] is brought to the full Senate for a vote,” Flake said from the Senate floor.

Flake is retiring this year and will be replaced in January by Rep. Kyrsten Sinema (D-AZ).

Flake’s new threat will block the Judiciary Committee from approving judicial nominations and sending them to the full Senate without help from Democrats.

Republicans hold a 11-10 majority on the panel and many of the most controversial nominees pass along party lines, meaning they would need either Flake’s vote or a Democratic senator to flip.

In making this threat, he’s attempting to hit McConnell on something he cares about quite a bit: his goal to push through as many conservative judicial nominees as possible.

It’s something McConnell has emphasized repeatedly and a message he came back to today while laying out his congressional priorities.

Flake’s decision comes after McConnell blocked him from bringing legislation to protect Mueller from being fired to a vote before the Senate.

The bill has been stalemated amid opposition from GOP leadership after it cleared the Judiciary Committee on a bipartisan basis.

The legislation would protect Mueller, or any other special counsel, in the event he is fired, but the bill has stalled amid opposition from GOP leadership.

The bill would codify Justice Department regulations that say only a senior department official can fire Mueller or another special counsel.

It would give a special counsel an “expedited review” of their firing. If a court determines that it wasn’t for “good cause,” the special counsel would be reinstated.