In her Wall Street Journal column published a week ago, Peggy Noonan characterized the first batch of President-elect Donald Trump’s cabinet picks as “normal Republicans.” For a few of the next choices however, she wrote that “it is impossible to tell if Mr. Trump is announcing appointments or trolling his enemies.” Those selections are so baffling that they have left large numbers of Americans, including many Republicans, scratching their heads.

Elected presidents have the right to choose the people they think will best help them carry out their agendas. But the Founding Fathers recognized that the judgments of future presidents would not always be unimpeachable. That is why the Constitution granted the U.S. Senate its advice-and-consent responsibility. If a president appoints individuals who are so patently unqualified for the jobs they are expected to do, as is the case with some of the president-elect’s current selections, then the Senate has a duty to step in and reject those candidates before they get the opportunity to do damage to the country.

The fear that many people now have is that the Republicans, who hold a majority in the Senate, will abdicate this responsibility. Due to the president-elect’s complete hold on the party, few Republicans, if any, are prepared to stand up to him these days. That is why he has been able to get away with so many things that, just a few short years ago, would have quickly ended any political career. Because of this dearth of people in today’s Washington who are willing to speak truth to power, I have been thinking a lot lately about George C. Marshall.

In his bestselling book, The Road to Character, David Brooks delved into the lives of nine world historical figures who rose to greatness from vastly different origins. Each of those individuals had an entire chapter of the book devoted to them. Essentially, each chapter was a mini-biography in which Brooks explored the family background and some specific formative experiences that helped shape the character of that individual. All nine of the people selected by Brooks were supremely impressive human beings, but the one I found myself revering the most was George Marshall, who served as U.S. Secretary of State and later Secretary of Defense, both under President Harry S. Truman, and was also the brainchild of the Marshall Plan.

Marshall was born and raised in Uniontown, a small town in western Pennsylvania. His father had been a successful businessman but had gone bankrupt when Marshall was a young boy, leaving the family impoverished. Marshall was a rather mediocre student whom almost no one, particularly his father and older brother Stuart, expected much from. Stuart had attended the Virginia Military Institute (VMI), and after elementary school, Marshall wanted to follow in his brother’s footsteps. One day, after he had disclosed his wish to the family, he overheard Stuart trying to persuade their mother not to let Marshall go to VMI, out of fear that he would disgrace the family name there. It was a pivotal moment in Marshall’s life. He set out to prove everyone wrong. Brooks states that “[Marshall’s] urgency to succeed came from hearing that conversation.”

Academically, Marshall did not perform particularly well at VMI, as expected. But he compensated for that with unparalleled hard work, attention to detail, and exceptional personal discipline that made a huge impression on everyone within the institution. In his senior year, he was named first captain, VMI’s highest rank.

During World War I, Marshall was sent to France to serve as assistant to the Chief of Staff of the American Expeditionary Force (AEF) for the 1^st Division. He was in that post when the senior U.S. Commander in the war, General John Pershing, visited the unit. Pershing found a division that was poorly trained and performing badly. He promptly gathered the unit and in front of everyone, lambasted the Commanding Officer and his Chief of Staff. Marshall considered the attack on his immediate bosses unfair. He knew that the shortcomings were not their fault, but rather the result of poor supplies, misplacement of troops, and lack of other essential equipment. He stood up and pointed out that those problems could be traced back to the headquarters that Pershing himself presided over.

Incensed by that public call-out, Pershing was about to storm out when Marshall held his arm to stop his exit. Every jaw dropped in the room. The assembled men thought that Marshall had ended his career. But he kept on making his case to Pershing, eventually forcing him to acknowledge that his own headquarters was part of the problem. “Well, you have to appreciate the problems we have,” Pershing said to Marshall, to which he replied, “Yes, General, but we have them every day and many a day, and we have to solve every one of them by night.”

The exchange made a huge impression on Pershing. Whenever he returned to visit the 1^st Division, he looked for Marshall to seek his counsel. Pershing later asked Marshall to serve as a member of the AEF operations staff, where the two worked closely together. When Marshall married his second wife in 1930, three years after his first wife died, General Pershing served as his best man. Such was the depth of the respect that Marshall had earned.

I have read elsewhere that there was an even greater display of courage by Marshall years later. While the U.S. was preparing for World War II in 1938, Marshall was appointed Deputy Chief of Staff of the War Plans Division in Washington, D.C. At a White House conference to discuss a proposal by President Franklin D. Roosevelt (FDR) to expand the United States Army Air Corps, Marshall was said to be the only attendee to disagree with the president. He argued instead for a focus on logistical support and training, and the build-up of a large ground army. Once again, those present at the meeting thought that by contradicting the president so openly, Marshall had perhaps ended his career.

Contrary to everyone’s fears, FDR appreciated Marshall’s willingness to speak up and disagree with him. Shortly thereafter, he appointed Marshall to the position of Army Chief of Staff, despite 34 other officers having rankings superior to Marshall’s at the time. When FDR was about to select someone to serve as Supreme Commander of Operation Overlord, Marshall was the obvious candidate, and he coveted the job. But FDR appointed General Dwight D. Eisenhower instead, saying to Marshall, “I didn’t feel I could sleep at ease if you were out of Washington.” Marshall had become indispensable to the president. In December 1944, he was promoted to the newly created rank of General of the Army, a five-star rank. He was the first American general to attain that rank.

Because of the current political environment in America, our nation urgently needs someone with the courage and integrity of George Marshall. The complete takeover of Washington by Republicans means that this individual must necessarily come from the party. That is why I think Senator John Thune, as incoming Majority Leader of the Senate, has to stand up and be counted. By some of his initial appointments, the president-elect has clearly demonstrated that he intends to follow through on his promise to upend our institutions. The goal, obviously, is to weaken them and bend them to his will. As the body tasked with vetting presidential nominations and either confirming or rejecting them, Senator Thune can do the nation a great service by using his power to disagree with the president-elect when necessary.

Having come from nothing to make something of himself, Marshall perhaps had the most to lose of all the people in the rooms where he so famously spoke truth to power. But that didn’t stop him from doing what he felt was right, whenever and wherever the situation called for. That is why I was so inspired after reading about him. That kind of character is extremely rare in this world. In the corporate, political, and whatever spheres we find ourselves in, the overwhelming majority of us constantly engage in self-preservation. That attitude is responsible for many of the problems and injustices we see all around us every day. The world would be a much better place if more of us acted with even a tiny fraction of Marshall’s courage and integrity.

Next summer, I plan to visit Dodona Manor, the home in Leesburg, Virginia, to which General Marshall retired after his many years of public service. It is now a public museum. I feel a strong urge to walk those grounds and pay homage to this great American—and human being. His biographies should be required reading at all levels of our society.