In your opinion, what is the most powerful speech in history?

Charlie Chaplin's final speech in the Great Dictator is probably up there.

I’m sorry, but I don’t want to be an emperor. That’s not my business. I don’t want to rule or conquer anyone. I should like to help everyone - if possible - Jew, Gentile - black man - white. We all want to help one another. Human beings are like that. We want to live by each other’s happiness - not by each other’s misery. We don’t want to hate and despise one another. In this world there is room for everyone. And the good earth is rich and can provide for everyone. The way of life can be free and beautiful, but we have lost the way.

Greed has poisoned men’s souls, has barricaded the world with hate, has goose-stepped us into misery and bloodshed. We have developed speed, but we have shut ourselves in. Machinery that gives abundance has left us in want. Our knowledge has made us cynical. Our cleverness, hard and unkind. We think too much and feel too little. More than machinery we need humanity. More than cleverness we need kindness and gentleness. Without these qualities, life will be violent and all will be lost….

The aeroplane and the radio have brought us closer together. The very nature of these inventions cries out for the goodness in men - cries out for universal brotherhood - for the unity of us all. Even now my voice is reaching millions throughout the world - millions of despairing men, women, and little children - victims of a system that makes men torture and imprison innocent people.

To those who can hear me, I say - do not despair. The misery that is now upon us is but the passing of greed - the bitterness of men who fear the way of human progress. The hate of men will pass, and dictators die, and the power they took from the people will return to the people. And so long as men die, liberty will never perish. …..

Soldiers! don’t give yourselves to brutes - men who despise you - enslave you - who regiment your lives - tell you what to do - what to think and what to feel! Who drill you - diet you - treat you like cattle, use you as cannon fodder. Don’t give yourselves to these unnatural men - machine men with machine minds and machine hearts! You are not machines! You are not cattle! You are men! You have the love of humanity in your hearts! You don’t hate! Only the unloved hate - the unloved and the unnatural! Soldiers! Don’t fight for slavery! Fight for liberty!

In the 17th Chapter of St Luke it is written: “the Kingdom of God is within man” - not one man nor a group of men, but in all men! In you! You, the people have the power - the power to create machines. The power to create happiness! You, the people, have the power to make this life free and beautiful, to make this life a wonderful adventure.

Then - in the name of democracy - let us use that power - let us all unite. Let us fight for a new world - a decent world that will give men a chance to work - that will give youth a future and old age a security. By the promise of these things, brutes have risen to power. But they lie! They do not fulfil that promise. They never will!

Dictators free themselves but they enslave the people! Now let us fight to fulfil that promise! Let us fight to free the world - to do away with national barriers - to do away with greed, with hate and intolerance. Let us fight for a world of reason, a world where science and progress will lead to all men’s happiness. Soldiers! in the name of democracy, let us all unite!

There are many, but I like Emma Goldman in Union Square, 1893:

Fifth Avenue is laid in gold, every mansion a citadel of money and power. Yet here you stand, a giant, starved, and fettered… You too,will have to learn that you have a right to share your neighbors’ bread. Your neighbors – they have not only stolen your bread,but they are sapping your blood. They will go on robbing you, your children, and your children’s children, unless you wake up, unless you become daring enough to demand your rights. Well, then, demonstrate before the palaces of the rich; demand work. If they do not give you work, demand bread. If they deny you both, take bread. It is your sacred right.

We're still fighting these battles today. The names have changed, but the game is the same.

I'll give a different kind of answer: Alexander's speech at Opis. This is not because I particularly agree with it on an ethical or personal level - Alexander was a warmonger who was trying to guilt-trip his troops who had been warring for 10 years to prevent them from returning home. It's more for the quality of the oratory, the fact that reading it, or especially listening to it being read aloud, I feel exactly what Alexander wanted me to feel, despite personal misgivings on an intellectual level. MLK is much more in line with my personal values.

Another difference, of course, is that this speech was recorded long after it was given, so it is likely not a word for word recollection of what was said, but rather, a historian's rendering of the general sense that was passed down orally through generations. As such, ancient speeches have the benefit that they may be a lot more elegant in the retelling than they were originally. But, on the other hand, it would have to be a very memorable speech to get that treatment in the first place.

I'm also a fan of Winston Churchill's wartime speeches.

Having listened to both the 'I've been to the Mountaintop' and 'I have a dream' speeches recently, I found the "somewhere I read..." part much more powerful than the "I have a dream..." part of the respective speeches. The ending to 'I've been to the mountaintop' is just beautiful.

Most powerful in a different way is "This is water" by David Foster Wallace. It brings out the
profundity in ordinary modern life. It's unpretentious, vulnerable, and just deeply human.

My answers are definitely biased by having access to the at least the audio. If I could hear the audio I might come to love most Eugene V Debbs's speech to the court upon being convicted of sedition.

I said then, and I say now, that while there is a lower class, I am in it, and while there is a criminal element I am of it, and while there is a soul in prison, I am not free.

and

As the midnight approaches, the southern cross begins to bend, the whirling worlds change their places, and with starry finger-points the Almighty marks the passage of time upon the dial of the universe, and though no bell may beat the glad tidings, the lookout knows that the midnight is passing and that relief and rest are close at hand. Let the people everywhere take heart of hope, for the cross is bending, the midnight is passing, and joy cometh with the morning.

I was about to say some of the ones you already quote so I will give you one very famous that is still very present today from the 1976 movie "network". I can't recommend it enough if you haven't seen it.

I don’t have to tell you things are bad. Everybody knows things are bad. It’s a depression. Everybody’s out of work or scared of losing their job. The dollar buys a nickel’s worth. Banks are going bust. Shopkeepers keep a gun under the counter. Punks are running wild in the street and there’s nobody anywhere who seems to know what to do, and there’s no end to it. We know the air is unfit to breathe and our food is unfit to eat, and we sit watching our TVs while some local newscaster tells us that today we had fifteen homicides and sixty-three violent crimes, as if that’s the way it’s supposed to be.

We know things are bad – worse than bad. They’re crazy. It’s like everything everywhere is going crazy, so we don’t go out anymore. We sit in the house, and slowly the world we are living in is getting smaller, and all we say is: ‘Please, at least leave us alone in our living rooms. Let me have my toaster and my TV and my steel-belted radials and I won’t say anything. Just leave us alone.’

Well, I’m not gonna leave you alone. I want you to get MAD! I don’t want you to protest. I don’t want you to riot – I don’t want you to write to your congressman, because I wouldn’t know what to tell you to write. I don’t know what to do about the depression and the inflation and the Russians and the crime in the street. All I know is that first you’ve got to get mad. (shouting) You’ve got to say: ‘I’m a human being, god-dammit! My life has value!’

So, I want you to get up now. I want all of you to get up out of your chairs. I want you to get up right now and go to the window. Open it, and stick your head out, and yell: ‘I’m as mad as hell, and I’m not gonna take this anymore!’

I want you to get up right now. Sit up. Go to your windows. Open them and stick your head out and yell – ‘I’m as mad as hell and I’m not gonna take this anymore!’ Things have got to change. But first, you’ve gotta get mad!…You’ve got to say, ‘I’m as mad as hell, and I’m not gonna take this anymore!’ Then we’ll figure out what to do about the depression and the inflation and the oil crisis. But first, get up out of your chairs, open the window, stick your head out, and yell, and say it: ‘I’m as mad as hell, and I’m not gonna take this anymore!’

When he says: ‘I’m a human being, god-dammit! My life has value!’ almost makes me cry.

I wonder what the impact of sound and video recordings has had on our answer to this question. For example, does the fact that we don’t actually know what the Gettysburg Address sounded like when Lincoln delivered it makes a difference? Does it make a difference to any of the thousands of other speeches that were made once and then disappeared into the ether without ever being recorded.

That's an interesting topic but might have benefited from a smaller scope. Few people are even close to the knowledge required to emit a barely informed opinion on the matter.

For what it's worth, FDRs regular talks on the radio during WWII are among the most beautiful, inspiring and ingenious uses of rhetoric in recent history. The nation needed lifting and he delivered it. Sometimes just thinking about FDR makes me emotional. He certainly made grave mistakes but was a wonderful human being nevertheless.

I'm not sure they're qualified as speeches, FDR himself avoided calling them that. But they may be according to current standards.

The most powerful speech for me at least was Philip Wollen's "a pig is a dog is a bear is a boy" at the St James Ethics and the Wheeler Centre debate. It's deeply moving and thought provoking. Honourable mention to "This is Water" by David Foster Wallace. It's important to keep one's narcissism in check.

It might not have been any literary masterpiece like some of these answers, but Kennedy's Moon Speech at Rice Stadium never fails to hit me with a train of emotion.

I would like to nominate Ted Nelson's video released today: FEATURE-LENGTH REPLY to "The Curse of Xanadu" (STRONG LANGUAGE WARNING).

For those that don't know Ted Nelson, here is his wiki page: https://en.wikipedia.org/wiki/Ted_Nelson.

Aragorn's speech before the Black gate.

Hold your ground! Hold your ground! Sons of Gondor, of Rohan, my brothers, I see in your eyes the same fear that would take the heart of me. A day may come when the courage of men fails, when we forsake our friends and break all bonds of fellowship, but it is not this day. An hour of wolves and shattered shields, when the age of men comes crashing down, but it is not this day! This day we fight!! By all that you hold dear on this good Earth, I bid you stand, Men of the West!!!

Or possibly Theoden's on the Fields of Pelennor before the charge of the Rohirrim to Minas Tirith.

Arise, arise, Riders of Théoden! Fell deeds awake, fire and slaughter! spear shall be shaken, shield be splintered, a sword-day, a red day, ere the sun rises! Ride now, ride now! Ride to Gondor! Ride now, ride now! Ride to Gondor!