"Mr. Trump’s biggest obstacle to vast power is not the separation of powers but the millions of federal employees who are supposed to work for him. Most of these employees have a strong sense of professionalism and are dedicated to the mission of their agency. They don’t take kindly to arbitrary orders from above. As President Harry Truman said ahead of Dwight D. Eisenhower’s presidency: “He’ll sit here, and he’ll say, ‘Do this! Do that!’ And nothing will happen.”I don't think the Founding Fathers saw this role for bureaucrats, but I think Prof. Posner is right, particularly in the Federal context. In other countries with more centralized bureaucracies, maybe a politician can topple the bureaucratic bulwark, but in the U.S. not so. I'd quibble a bit about the "professionalism": conflicting alliances with Congress and private interests may be as important..
To make things happen, Mr. Trump will need to get loyalists into leadership positions of the agencies, but to do so, he will need the cooperation of the Senate (or he will need to aggressively exploit his recess appointment powers). Moreover, the small number of politically appointed leaders enjoy only limited control of the mass of civil servants. These employees can drag their feet, leak to the press, threaten to resign and employ other tactics to undermine Mr. Trump’s initiatives if they object to them. They’re also hard to fire, thanks to Civil Service protections."
When politicians, like the Republicans now, go after bureaucrats in the VA or IRS, they should remember there's a reason we have civil service rules.