President Trump, with first lady Melania Trump, speaks to guests during the military families picnic on the South Lawn of the White House on July 4. (Calla Kessler/The Washington Post)

Welcome back to The Monkey Cage’s weekly presentation of Founding Principles, a series of short videos designed to explain American government and how it works — in theory, and in practice.

So far we’ve looked at various aspects of the separation of powers — as represented in both the branches and levels of U.S. government — and begun to trek through the branches themselves in more detail. Last week we explored Article I of the Constitution, which established the Congress. This week it’s Article II and the presidency. There’s lots to talk about, even setting aside current events.

For one thing, we talk a lot about the “imperial” presidency. The president of the United States is often called “the leader of the free world,” the most powerful person there is. Yet Richard Neustadt’s classic book “Presidential Power” starts with a startling premise: The key thing to understand is actually about presidential weakness. And, constitutionally speaking, that’s a good place to start.

The history of the American presidency is the history of how presidents have tried to overcome that structural weakness. Luckily for U.S. chief executives, Article II (as the great legal scholar Edward Corwin commented) is “the most loosely drawn chapter of the Constitution. To those who think a constitution ought to settle everything beforehand, it should be a nightmare.”

So there’s a lot of room to define presidential power in practice — from the creative use of formal powers to the art of “going public” to the growth of the “institutional presidency.” Take a look to see some of the ways that’s been done over time.

Want to know more? Here’s the series so far:

Too many Americans know too little about the Constitution. Here’s how you can fix that.

Happy birthday, America! Here’s what you need to know about federalism.

Why does Congress have such a hard time passing laws? Let’s blame the Constitution.