When you’re a five-star General, like Dwight D. Eisenhower was, you give an order and people jump. But after Eisenhower was elected president in 1952, the outgoing president, Harry Truman, predicted trouble for the hero of D-Day.

Pointing at his desk in the Oval Office, Truman said “He’ll sit right here and he’ll say do this, do that! And nothing will happen. Poor Ike—it wont be a bit like the Army. He’ll find it very frustrating.”

And so it may be for Donald Trump.

When he takes office on Jan. 20, he’ll have vast power. He can send troops into battle. He could rain bombs on our enemies. He can nominate whoever he wants to the Supreme Court. He can convene Congress or adjourn it. Grant pardons to anyone. Perhaps he could even build a wall on, oh, I don’t know, the Mexican border.

But try and fire a lowly bureaucrat in some obscure federal agency? Good luck with that.

In certain respects, Trump is about to find out that as chief executive of his own company, he has more leeway in that ecosystem than he’ll have as president. The CEO of a privately held company can do whatever he wants, and doesn’t have to answer to anyone. Not shareholders. Not Wall Street analysts. He can hire and fire at will. It must be great to have that kind of power—and money—and not having to explain yourself to anyone.

Presidents are different. We think of them as all-powerful figures. But the fact is, presidents control just one-third of the federal government: the executive branch. There’s also the legislative branch (Congress) and the judicial branch (Supreme Court). Our founding fathers designed it so that each has the same amount of power, and has a say in what the other branches can do. It’s a system of checks and balances. The CEO of a privately held company has no such constraints.

How could President-Elect Trump affect NATO?

Counting the military, there are some 4.1 million people on the federal payroll. Presidents can hire or fire maybe 4,000 of them—about 0.1%. The vast majority are protected by civil service rules that, in some cases, date back to the ’90s—the 1890s.

All companies have lazy, incompetent employees; the federal government is certainly no different. Trump would like to overhaul regulations to make it easier to get rid of underperforming workers. It’s a good idea. It requires Congressional approval, though, and lawmakers, eager to protect jobs in the districts back home, might be less willing to go along then the new president presumes.

In an example of just how hard the could be, both the Bush and Obama administration have consolidated hundreds of military bases over the last decade. It has meant years of tooth-and-nail fights with lawmakers and lobbyists who rarely, if ever, want to give an inch. It’s that kind of mentality and situation that can drive presidents nuts.

Trump has supreme confidence. He’s aggressive. He’s energetic. His enemies have consistently underestimated his intelligence. He’s not a creature of Washington and says he’s in no one’s pocket. All this is an appealing elixir to voters, as is his steamroller, my-way-or-the-highway approach. I like those qualities myself.

In terms of effective governance, however, it will be problematic. He brags about being a great negotiator. That’s the true skill Trump will need to get his way in Washington. Lyndon Johnson and Ronald Reagan are modern-day examples of how this can work, and he could learn a thing or two from these political masters.

Read:We’ve never had an outsider president like Trump