The Madisonian system, about which we seem to learn more during crises than in civics classes, assumes that majorities and minorities will shift from issue to issue, so that a winner is chastened, and a loser comforted, by the knowledge that their roles might be reversed during the next controversy. For James Madison, this was the key reason it was irrational for voters to exploit momentary advantages to violate liberties: The tables might turn on them quickly.

When all of politics is seen through one person, those realignments harden into the uniform and often unchanging views of the president. Presidential politics bulldozes the subtleties and nuances that should define serious politics. The president’s perceived advantage or disadvantage defines every coalition and controversy.

At the same time, the proper constitutional distance between the president and the public is erased. Alexander Hamilton wrote in Federalist 71 that a president might have to protect the public against itself:

When occasions present themselves, in which the interests of the people are at variance with their inclinations, it is the duty of the persons whom they have appointed, to be the guardians of those interests; to withstand the temporary delusion, in order to give them time and opportunity for more cool and sedate reflection.

This requires a distance that the accelerating personal relationship between presidents and voters does not allow. As George F. Will has emphasized, Franklin Roosevelt began his fireside chats by addressing his listeners as “friends,” suggesting that there was a personal relationship between presidents and their constituents. Yet presidents are not friends. As Mr. Will notes, their job is to lead the executive branch of government. We expect different qualities from personal friends and public leaders. Conflating those roles makes it more difficult for leaders to do the job we assign them with the distance and judgment it requires.

The coronavirus crisis has taken this personal presidency to an insidious new level. Recently, the Trump administration took two steps that historians may register as landmarks of the personalized presidency. The Centers for Disease Control and Prevention mailed households a postcard blaring in all capital letters: “President Trump’s Coronavirus Guidelines for America.” And Mr. Trump reportedly indicated his preference that relief checks from Congress’s $2 trillion stimulus plan bear his personal signature. Through measures like these, the president emerges not only as our friend, which was problematic enough, but also as our personal caretaker. We are now to see public relief as beneficence flowing from one man.

The hijacking of the C.D.C. to serve the obvious electoral interests of a president seeking a second term is dangerous not only constitutionally but also to public health. There is always a delicate balance between politicians deferring to experts and making their own judgments. Unsupervised experts can display too much certainty and too little ability to balance the myriad competing ends involved in politics.