Sen. Jeff Flake (R-Ariz.) declared on Wednesday his intent to oppose all of Donald Trump‘s judicial nominations until legislation protecting special counsel Robert Mueller is voted upon.

JEFF FLAKE TO OPPOSE JUDICIAL NOMINEES

Standing before the Senate, the Arizona senator said, “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.”

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Flake’s participation is likely needed for Trump’s picks to be approved. The panel currently has a 11-10 makeup favoring the Republicans, although there would be an impasse without Flake unless one of the Democrats on the panel flipped. Meanwhile, the Senate itself is more forgiving to Mitch McConnell, giving him a 51-49 majority in favor of their nominees when it comes to vote on the floor.

Flake was recently blocked from introducing a bill to shield Mueller by McConnell, spurring Flake to make his current threat. Should the bill be passed, it would protect Mueller and other special counsel members should they be fired. The legislation would add that only a senior department official can fire special counsel personal. They would then have an “expedited review” of their firings and would be reinstated if it was determined they were not fired for a “good cause.”