Here's a story about what happens when the boss thinks he's the smartest person in the building. On Saturday, Anthony Scaramucci—yes, the Mooch, the guy who had that famously brief stint in the Trump White House—shared an anecdote that he says perfectly illustrates what he views as Donald Trump's core leadership flaw. It's a story from right after the 2016 election, and it's about who you hire when you win.

The criticism comes as Scaramucci has been publicly attacking Trump's recent push for sweeping new tariffs, a move that triggered a sharp global market selloff. He seems to be connecting the dots between a personal leadership style and its very public, market-moving consequences.

In a post on X, Scaramucci recalled a moment when, he says, Michael Bloomberg called Trump after the election to offer some advice: staff up with people who would challenge you. According to Scaramucci, Trump's reply was, "That's impossible. There's nobody smarter than me." Scaramucci wrote that he witnessed the exchange himself.

The Leadership Theory of a Shrinking Room

Scaramucci's point isn't just about one boastful comment. He's arguing it reveals a management philosophy built on certainty, not debate. The idea of effective leadership, in his view, is to build a team that tests your assumptions. A leader who insists on being the top mind in every meeting, he warns, eventually finds the talent around him starts to... thin out. The room gets smaller.

In the same post, Scaramucci noted that journalist Maggie Haberman later corroborated a similar line in her book, "Confidence Man." For Scaramucci, the remark explains how decision-making can drift away from being about the best outcomes and toward feeding an ego.

And he sees this critique playing out in real time with policy. Scaramucci has argued that Trump's inner circle on trade isn't built to push back. After Trump moved to slap new tariffs on most major U.S. trading partners, Scaramucci posted on X, "There is stupid and then there is Donald Trump Stupid: DTS. A new global low."

He also took aim at the advisers, saying the administration was operating inside an "echo chamber of stupidity" on trade. These comments landed right after China answered the U.S. tariffs with retaliatory measures of its own.

From Tariffs to (Hypothetical) Invasions: The Cost of No Dissent

This isn't Scaramucci's first warning about the potential fallout from aggressive U.S. moves made without sufficient internal challenge. He's previously discussed the repercussions of aggressive foreign policy, notably once labeling a hypothetical U.S. invasion of Greenland as "one of the most self-destructive foreign policy moves imaginable."

He emphasized that such an action wouldn't just be viewed as an illegal war of aggression against a NATO ally; it could shatter the core trust within U.S. alliances and wreak havoc on financial conditions. The thread connecting his Greenland comments to his tariff critique is the same: policies shaped in an environment that discourages dissent carry massive, often unforeseen, risks.

When Markets Vote on Leadership Style

The critics of the tariff push have a straightforward argument: higher import costs and retaliation from other countries boomerang back onto U.S. economic growth. The market seems to be listening. The size of the Dow's one-day slide after Trump's "Liberation Day" tariff announcement was a clear signal of how quickly investors can repriced economic risk when new policies emerge.

So, Scaramucci's leadership critique and his tariff attacks are really two sides of the same coin. Both hinge on the claim that Trump resists dissent and prefers to surround himself with reinforcement instead of challenge. In his post on X, Scaramucci wrapped it up with a warning that applies to boardrooms and the Oval Office alike: when a leader believes he's always the smartest in the room, the room—and the pool of talent willing to be in it—gets smaller over time. And sometimes, the stock market charts the shrinkage in real time.