Here’s what fascinates me about political rhetoric: when a politician really seeks to be as compelling as possible — to entice people into moral sympathy with a vision, to elicit trust from the voters, to touch the very core of our aspirations for life and politics — the language of liberty serves the cause best.

Freedom is what inspires and ennobles us.It’s not the promises of an iron fist that speak to us, but rather the opportunities provided by freedom. It is not the power of politics they emphasize but the power of people on their own.

We’ve seen it often over the decades but rarely more poignantly than in President Obama’s speech at the Democratic National Convention. Here we have a president who has spent eight years constructing an apparatus of executive rule, pushing out the boundaries of government imposition as far as possible, in every area of life, most conspicuously in education, surveillance, foreign policy, gun rights, and health care.

And yet, when it comes time to make a case for his party as against the Republican Party, and to make the case for his chosen successor, he gives us these awesome and inspiring words:

We are not a fragile or frightful people. Our power doesn't come from some self-declared savior promising that he alone can restore order. We don't look to be ruled. Our power comes from those immortal declarations first put to paper right here in Philadelphia all those years ago; We hold these truths to be self-evident, that all men are created equal; that together, We, the People, can form a more perfect union. That's our birthright — the capacity to shape our own destiny.That's who we are. That's our birthright — the capacity to shape our own destiny…. America has never been about what one person says he'll do for us. It's always been about what can be achieved by us, together, through the hard, slow, sometimes frustrating, but ultimately enduring work of self-government…. My grandparents explained that they didn't like show-offs. They didn't admire braggarts or bullies. They didn't respect mean-spiritedness, or folks who were always looking for shortcuts in life. Instead, they valued traits like honesty and hard work. Kindness and courtesy. Humility; responsibility; helping each other out…. Demagogues will always fail in the end.That's why anyone who threatens our values, whether fascists or communists or jihadists or homegrown demagogues, will always fail in the end. That's America. Those bonds of affection; that common creed. We don't fear the future; we shape it, embrace it, as one people, stronger together than we are on our own.

Exactly: we don’t look to be ruled. Our value as a people comes not from the top down but from within — from character, resilience, decency, all of which emanate from freedom itself.

Now, you can read that as an attack on Donald Trump, which it surely is. But what is the best way to achieve that? Where is Trump most vulnerable? President Obama found it: Trump aspires to be a strongman, and America is not about that. It’s a very effective critique, even if it emanates from the wrong source. For the Democrats to make such a critique is hypocrisy of the highest order.

Are we really supposed to pretend that the top-down imposition of Obamacare never happened? That Common Core didn’t come to dominate American education? That Obama played no role in the vast expansion of digital surveillance? That Obama’s (and Clinton’s) foreign policy did not extend the mindless war-making of his predecessors and did not unleash unholy hell all over the Middle East and Europe, setting off a catastrophic refugee crisis and spreading the terror threat throughout the world?

We look to be free of rule.Yes, we are supposed to forget all that. And if we set that aside, there is a wonderful lesson to be learned in the newest iteration of Obama: we don’t look to be ruled. We look to be free of rule.

It has also been generally true that presidents give their best – and most liberty-minded – speeches in the twilight days of their power. Think of George Washington’s Farewell Address and his remark that “the great rule of conduct for us in regard to foreign nations is, in extending our commercial relations, to have with them as little political connection as possible.” Consider Eisenhower’s final warning that “we must guard against the acquisition of unwarranted influence, whether sought or unsought, by the military-industrial complex.” Or Reagan’s final speech, reiterating the vision of America as a “Shining City on a Hill,” and proclaiming: “Countries across the globe are turning to free markets and free speech and turning away from the ideologies of the past.”

Eventually, they see through the myth of power.We might ask ourselves: why do powerful people turn to liberty-oriented themes in the last days of their power? Perhaps it is because, in the course of their rule, each of these people gradually discover that ruling is not all it is cracked up to be.

They arrive in their offices with grand ambitions, the perception of a public mandate, and huge plan for making the world conform. What they face is a vast and implacable bureaucracy, a legacy of centuries of lawmaking, a professional class of managers and fixers at all levels of government, an army of special interests and lobbyists who are ready for war to the knife over the slightest changes in the operations of government, and a populace who just never seem to get with the program.

And there are only so many hours in a day. What presidents must probably discover is not how much power they have, but rather the opposite: how much power the apparatus of government has over them. Between all the meetings with dignitaries, the travels, the speeches and public appearances, the flattering of big shots that swirl in and around the White House at all hours, they are wholly dependent on their advisers, who are in turn dependent on theirs, who are in turn dependent on theirs.

When presidents finally get a chance to act, they make a hash of it.And yet there are moments when presidents do seem to act with genuine authority extending from their own volition. Bush invaded Iraq, and look what that did to the world. Obama threw himself behind Obamacare, with the conviction that a vast array of experts had vetted the system and pronounced it good. The whole thing blew up and wrecked much of what was good in American healthcare. The legacy of his signature legislation is so unpopular that mention of it was reduced to just one oblique reference in his convention speech.

So, yes, the experience of governing can be truly humbling. I can’t imagine the trauma that this is going to cause Trump, whose only experience has been in bossing people around in the private sector in businesses he owns. No one in particular owns government, and the bureaucracy is never more implacable than when faced with someone who purports to be in charge of them.

If presidents were to be honest with themselves, they would have to admit that they were fools to believe that the government, much less the whole nation, could be ruled by their will alone. It’s preposterous to believe that 300 million people — each person with a mind, heart, will, soul all his or her own — can be ruled by anyone.

Someday I hope to read an honest autobiography of a former president:

I arrived flush with anticipation of changing the world. Crowds screamed my name and cried out for me to bring justice, fairness, equality, and happiness to the country. I discovered over time that I personally had very little power at all, and the little I did have was dangerous because the results were nothing like what I had anticipated. I pretended to be important. I kept up appearances. People doted on me constantly. And yet I learned, gradually, that I was just one man, and the system swallowed me completely. And that’s probably a good thing too because, in the end, I’m no different from anyone else, no more or less capable, no more or less knowing and brilliant. My main talent was in campaigning and here I excelled. As for governing, I wouldn’t wish it on anyone.

Or as Obama beautifully summed it up: “We don’t look to be ruled.”