Will Paul Ryan unshackle himself from Donald Trump and give a full-throated defense of the rule of law? Now that he has announced his retirement from Congress, we urge him to do so.

Ryan must be clear:  Any attempt by the president to quash the investigation of special counsel Robert Mueller is an attack on the rule of law. The House speaker should throw his support behind legislation to protect Mueller.

Ryan will leave behind a legacy of honest, thoughtful conservatism — he fought for what he thought was best for his constituents and the country, based on a vision of smaller, less intrusive government and personal freedom.

But Ryan’s decision to leave Congress, while a blow to Wisconsin’s political might, could be good for our democracy if Ryan finds his voice.

If Trump moves to fire Mueller or his boss at the Justice Department, Deputy Attorney General Rod Rosenstein, Ryan and his colleagues in Congress must be ready to act. And not just with words. They should throw their support behind a bill that would protect the special counsel.