In a matter of weeks Pete Buttigieg rose from relative obscurity to national prominence. A successful CNN town hall in early March launched him into the 2020 conversation, and an impressive first-quarter fundraising haul made clear he is a serious candidate. His youth, charisma, and dizzying ascent have some thinking he’s a top contender to inherit Barack Obama’s mantle.

We worry that Jimmy Carter might be the more apt comparison. Like Buttigieg, Carter was a man of sharp intellect, a veteran, and a straight-shooting political outsider who pledged to address the country’s sense of crisis by restoring honesty and decency to an Oval Office tainted by vulgar political corruption. But Carter’s somewhat disastrous time in office proved those qualities don’t automatically translate into an effective presidency — and should serve as a cautionary tale for Buttigieg’s growing fanbase.

A recent interview escalated our worries. “In many ways, that moral or tonal dimension of leadership is as important or more as the actual policies that they put forward,” Buttigieg said last week when discussing political leaders. That quote may make for good rhetoric. But it suggests he doesn’t understand the job he’s running for.

His particular misunderstanding of the presidency is different than the more common kind. People typically drastically overestimate the president’s ability to carry out a specific legislative agenda. That tendency to disregard the messy reality of Congress is why we see presidential campaigns dominated by legislative laundry lists.

Buttigieg has not fallen into that trap — far from it. Instead, he has yet to put forward a comprehensive agenda of any kind, substituting fuzzy concepts of moral leadership for actual policy goals. Unfortunately, that brings him no closer to understanding the actual role of the president than the legislative visionaries.

The fact that the president does not write laws doesn’t mean they cannot implement an agenda. The main thing the leader of the nation’s executive branch does, it turns out, is lead the executive branch. And you don’t do that by acting as a moral exemplar — you do it by identifying nominees for hundreds of high-level positions across the government, and leading them toward achieving your goals.

Those appointees don’t write laws, but they have broad power to interpret and implement them. While such actions and nonactions are often overlooked, they frequently have greater consequence than the actual laws a president signs or vetoes.

Buttigieg should understand this: The very topic he was discussing when he made his comment about moral leadership illustrates how effectively executive power can harm regular people when deployed for that end.

Buttigieg was speaking about the anti-gay bigotry of Vice President Mike Pence. He is right to be appalled — we share his revulsion. But it’s not Pence’s moral tone that is making the United States a less equal place for the LGBT community — it’s the people his administration has appointed across the breadth of the executive branch, who are wielding their power to carry out an under-the-radar, policy-based battle against equality. The Human Rights Campaign’s “Trump’s Timeline of Hate” shows how Trump appointees at the departments of State, Homeland Security, Education, Justice, Health and Human Services, Housing and Urban Development, and Commerce have wound back equality on a daily basis.

It’s clear that Buttigieg — and any other Democrat — would replace these appointees with less hateful people. It’s equally clear that having a president and vice president who embody hate sends a terrible message to all Americans, particularly the most vulnerable. But it’s worrying to see Buttigieg viewing the presidency as principally about sending a message of unity, rather than about wielding power to implement policies, including those that might antagonize powerful interests.

Consider how the rules passed in response to the 2008 financial crisis have been ripped up under President Trump. One bad piece of Wall Street–friendly legislation passed by the Republican-controlled Congress is partly to blame, but Trump’s appointees have been even more destructive. While legislators left key regulations governing the country’s largest banks intact, Trump’s appointees have put them on the chopping block.

That’s what has happened to the Consumer Financial Protection Bureau, whose first director was appointed by Obama. Under his leadership, the bureau aggressively pursued cases of consumer abuse, ultimately returning, by its estimate, almost $12 billion to nearly 29 million consumers who had been wronged by the financial industry. Under new leadership installed by Trump, the CFPB is more interested in helping financial companies than in holding them accountable. Enforcement actions have fallen by more than 54%.

So far, Buttigieg is running more on a contrast between his decency and Trump’s indecency than a contrasting plan for running the government. Just take a look at his website, which sells “Pete’s Got Heart” T-shirts, but lacks an “Issues” or “Policies” page. It hasn’t hurt so far, given the more than $7 million he’s raised and the surge of attention he is receiving.

In the wake of this country’s last openly corrupt administration, Americans similarly threw their support behind a man who was the antithesis of the tainted, disgraced president. They voted for Jimmy Carter, a brilliant polymath whose upbeat brand of personal integrity projected an energetic, uncynical rebuke to Richard Nixon. Carter was also famously incapable of managing his executive branch effectively.

Today Carter is a beloved character best known for his heroic post-presidential efforts. His time in the White House? It, by contrast, did not work out well.

Carter’s problem, his former speechwriter James Fallows wrote in 1979, was that he expected that “organizations would run in practice, as they did on paper,” without any guidance or input. He took it as a given that the loyalties of his appointees’ “would still lie with the larger interests of the administration,” and thus turned his attention to micromanaging his legislative agenda. But he struggled to “explain his goals and thereby to offer an object for loyalty larger than himself,” Fallows wrote.

As a result, he gave his appointees no sense of the larger interests to which they were expected to be loyal. Untethered and uncoordinated, his Cabinet secretaries ended up working at cross-purposes and getting into territorial fights as they guessed at how to do their jobs. A detailed policy platform would have provided Carter’s administration with the organization and sense of purpose it never had. However, Carter responded to this chaos not by altering his management style but instead by asking his entire Cabinet to resign, further contributing to the sense that his administration was in chaos, and cementing his political demise the following year.

It is no shock that some Americans feel drawn to Buttigieg, a man who is indeed in many ways Trump’s antithesis. Not only does he read widely, but he does so in multiple languages!

And yes, it is great if a president is smart and sets forth a moral vision. But it’s nowhere near enough. We need candidates, including Buttigieg, to show a vision for how they will staff their administration and how they will run it. Absent concrete commitments to policies and indications of a plan to implement them, moral leadership simply doesn’t get the job done.