For as long as there has been a Capitol Hill, a secret list has circulated informally among staffers there bearing the names of the most difficult members of Congress to work for. Any staffer today who has worked on the Hill long enough is familiar with the list and the names that perennially appear there.

Members of Congress who make the list are there because they disrespect or harass their staffs. They throw shoes, belittle or spit cutting insults in dark corridors outside meeting rooms. Even without asking, a careful observer can quickly identify a member of Congress on the list — they need only to gauge the caliber of the men and women in their orbit. The officials with the worst reputations often have the least talented and least experienced staffers. The same is true of American presidents.

American presidential history sags with the weight of instructive and cautionary tales on this subject.

Consider the difficulty President Truman experienced attracting and retaining talent in his first year in office. After Franklin Roosevelt died, staffers left the government in droves, not wanting to work for his successor, a man whom many perceived as grossly inadequate in comparison to the legendary FDR.It was only when the capable and gifted Clark Clifford joined Mr. Truman’s team that the president began to get a firm handle on things.

In contrast, consider Ronald Reagan’s success in his first year. Reagan understood the importance of surrounding himself with A-list staffers, having served as the governor of California for two terms. When he was elected president, he asked James A. Baker, one of the most gifted political operatives in Washington, to be his chief of staff. One of the reasons Reagan was able to attract a man of Mr. Baker’s caliber was the president’s reputation as a generous leader with a genuine interest in letting the men and women around him shine. With Mr. Baker at his side, Reagan achieved arguably one of the most successful first two years of any president in history.

During the last presidential campaign, one of the main arguments used by President Barack Obama for why candidate Donald Trump was so ill-suited for the presidency was his temperament. Mr. Obama was of course referring to how he thought a man of Mr. Trump’s personality would react under the stresses of office, but he might also have been referring to the many ways Mr. Trump’s reputation might lead to his inability to attract competent and experienced advisers to serve him.

American voters have learned the hard way that selfish, difficult men make selfish, difficult presidents. And when such men sit in the White House, we all pay the price.

Americans suffer when a twenty-something, just out of college, with no background in medicine and no experience running an institution of any consequence, is appointed deputy chief of staff at the White House Office on National Drug Control because the president can inspire no one of competence to step forward.

Americans suffer when policy matters that have stymied giants of the global foreign affairs community for decades are placed in the hands of abject novices and when responsibility for consequential immigration policies are delegated to advisers who have done little more in their careers than observe these matters from the margins.

And Americans suffer when federal agencies, charged with ensuring the cleanliness of our air and water and tasked with protecting our sleeping children at night, are bled white of the gifted, experienced and wise men and women who work there because they can no longer stomach our nation’s leadership.

President Lincoln once famously said, “character is like a tree and reputation like its shadow.” One can extend his sentiment one step further and say that in a president’s case, his shadow is the men and women who choose to associate themselves with him. These men and women are not only a reflection of the quality of his leadership, but also of the content of his character.

K. Ward Cummings is the author of “Partner to Power: The Secret World of Presidents and their Most Trusted Advisers.” He wrote this for The Baltimore Sun.