Many recent comments about special counsel Robert S. Mueller III and his investigation have been regrettable and undeserved. I was surprised to see President Trump’s lawyer, Rudolph W. Giuliani, a respected former U.S. attorney, suggest this week that Mueller is “trying very, very hard to frame” the president, echoing comments made by the president himself that the investigation is “a Witch Hunt.” Those comments are the antithesis of who Mueller is and how he operates.

I know Bob Mueller as a colleague in law enforcement and as a friend, and I highly respect his judgment and moral compass. Mueller is the right person to investigate Russia’s apparent assault on our democracy. He possesses the skills and discipline necessary to perform his role, and his past leadership as head of the Justice Department’s criminal division and as director of the FBI leave no doubt as to his ability to evenhandedly conduct significant investigations. He is serious but not sensational and loyal to the rule of law.

Mueller must put all applicable evidence before an impartial grand jury that will decide whether to bring charges. We must let him do his job.

It is disconcerting to witness the unfair attacks on the Justice Department now occurring; they erode public confidence and corrode the integrity of a core principle of our country. Our country must not let hyperpartisanship diminish the rule of law. That is not who we are, and it isn’t what we should ever become. I have great confidence in the special-counsel process. Indeed, my party has always stood with law enforcement, recognizing that its job is both difficult and essential. Law-enforcement officials ranging from state and local police to FBI officers in the field to prosecutors and judges must be able to do their work without fear of political retribution.

I urge all members of Congress to become more vocal in their defense of the rule of law. Elected officials must stress unambiguously their support of the role of the special counsel and guard his right to pursue this investigation in a fair and impartial manner. Through whatever means members of Congress deem appropriate, they must defend the rule of law and the integrity of the special counsel’s mission.

As John Adams said, our country is “a government of laws, and not of men.” This founding principle of our democracy must be protected. We will be remembered by what we say and what we do in this challenging time in America’s history. We must all speak out and work to protect the special counsel’s investigation from interference. As Republicans, we owe that much to our party. As citizens, we all owe even more to our country.