Dear President-elect, here are a few things you need to know about Washington

Dear President-Elect Trump,

Welcome to Washington — a town that you and your supporters love to hate. There have been presidents before you that came to office swearing to “drain the swamp.” And they failed. So what is it about the federal government that makes it so hard to change? Millions of horrid, incompetent, self-serving bureaucrats? A Congress that is bought and sold?

What you will discover Mr. President, is that it is none of the above. What makes the government so hard to change is a quaint notion — it’s called the rule of law. Every penny spent on an “incompetent bureaucrat” or a stupid program is spent according to a law that has been passed and that you would need to undo.

What does this mean for you?

First, you can’t just fire people. The United States adopted a civil service system at the end of the 19th century that is protected from political interference. I know you harbor fantasies of walking into some large federal building and saying “YOU’RE FIRED.’’ You can try but it won’t work. You will have to change the law first, and then you might discover that as much as Americans hate bureaucrats, every other country in the world without a professional civil service is the kind of country where no American wants to live.

Second, you can’t move money. In February, you will be required to spend hours and hours putting together your first budget. Warning: It will be boring. And the budget is HUUGE! But even if you overcome the boredom, the first thing you’ll discover is that out of a whopping $3.8 trillion budget you can’t touch the $2.3 trillion spent on Social Security and other entitlements and you can’t touch the 6 percent that goes to interest on the federal debt.

OK, so that leaves you about 44 percent of the budget to shape as your own. Go to it. Get rid of all that waste. But — and you’ll have to get used to this — you are not a dictator. You have to send the budget to Congress, and even a Republican Congress will be particularly fond of a lot of the things in it.

But even if Congress won’t nix entire departments, you might think that you can shape those departments to your liking. WRRONG!!! The federal government operates under a set of rules that are designed to impede managerial discretion to a degree unheard of in the private sector. Because of the way Congress writes and passes budgets, many agencies find that it is nearly impossible to transfer money from one part of their budget to another without going back to Congress and asking for “reprogramming authority.” Of course, the rationale behind this law is to keep the executive branch from spending money on things that Congress has not approved. You can, of course, ask them to change that. Good luck.

That leaves executive orders. What about them? During the Obama administration, both the left and the right spun a lot of nonsense about executive actions. Obama talked them up as a way to get around his impotence when it came to dealing with a Republican Congress. And Republicans talked them up as a way to show that Obama was getting away with things they disapproved of. In fact, executive orders only work when Congress lets them work. Every time in recent history that a president has tried to do something via executive order that is opposed by Congress, the courts have struck it down because it violates the separation of powers. That’s in the Constitution. So you can undo many of Obama’s executive orders, but you can’t do things on your own that Congress opposes or that contradict law.

And what about your more specific promises? Building that wall? Sure. A lot of Americans think it’s a great idea, but you will have to go to Congress and ask them for an appropriation to do it. This could go on for quite some time. (And then you’ll have to fill in all the tunnels under the wall.) And what about deporting all those illegal aliens?. You can start, but things will get rough once the television cameras begin to film all the toddlers left at day care as their moms and dads are rounded up from their workplaces.

And of course you will get rid of Obamacare. But that requires sending a bill to Congress. It is now law — you can’t just sign it away on the first day. And once it gets there, people will be reminded that there are things they like about it — how about the removal of the piece of it that prohibits an insurance company from turning you down for a pre-existing condition? Congress will be tempted to keep the provisions that the public likes and then the insurance companies will get upset. So good luck with that one.

This is just a little introduction to Washington, and it doesn’t even get to foreign policy or what may happen to the stock market once you start undoing the global economy.

How long before you begin to wonder why you wanted this job?

Elaine C. Kamarck is a Senior Fellow at the Brookings Institution and author of Why Presidents Fail And How They Can Succeed Again. She is a superdelegate to the Democratic convention.