Sometimes, words on a page for a speech, no matter how carefully considered and composed, are less gripping than words that come, unbidden, to a speaker, who then goes off-script in an exquisite improvisation suited to the moment and makes history.
In this case, it was four words, uttered by the Rev. Martin Luther King Jr. when he addressed more than 250,000 people on the Washington Mall in 1963 -- the 50th anniversary is on Wednesday -- that lifted a good enough speech off the ground into full, soaring flight.
But how did "I have a dream" find its way into that historic address by the civil rights leader, Baptist preacher and advocate of nonviolent civil disobedience?
We'll get to that in a minute, but first a word about cliches.
King had used the "dream" refrain before, most recently at a fundraiser in Detroit, but Wyatt Walker, one of the advisers helping him draft the speech, was less than impressed, according to Gary Younge, author of a new book called "The Speech: The Story Behind Dr. Martin Luther King Jr.'s Dream."
"Don't use the lines about 'I have a dream,' " Mr. Walker told King the night before the Aug. 28 march. "It's too trite, it's cliche. It's been used too many times already."
King had been so busy with logistical planning for the march that the speech was almost an afterthought, and he was forced to resort to that time-honored ritual of college students everywhere: He pulled an all-nighter, finishing at 3:30 a.m. The pressure was on for an oration that would be received, he said, "like the Gettysburg Address."
The words "I have a dream" were not in the finished text, which borrowed from many of King's previous addresses, the Bible, Shakespeare and patriotic songs. He employed classic rhetorical strategies taught in speechwriting classes, using repetition and analogy.
But later that day, by the time King launched into the speech's closing words, exhorting the throng to "Go back to the slums and ghettoes of our northern cities, knowing that somehow this situation can and will be changed," he still hadn't found his real voice, the one that would transform an intent, silent audience into a state of rapture.
King hesitated in the silence, and according to Clarence Jones, one of his advisers, a voice cried out. It was Mahalia Jackson, the great gospel singer. "Tell 'em about the dream, Martin!" shouted Jackson, who had been impressed by his use of the "dream" language in an earlier speech.
Suddenly, King the orator stopped reading his text and became King the Baptist preacher.
"Even though we face the difficulties of today and tomorrow, I still have a dream," he began -- much to the chagrin of his startled adviser Mr. Walker.
By the time the last "Free at last!" echoed down the Mall, Mr. Walker and King's other advisers knew they had a winner, although it would take years before the speech would be called the greatest of the 20th century -- in 1999, in a survey of the country's top scholars of rhetoric.
That Mahalia Jackson played a role in making it so is indisputable, said Mr. Jones, even though King later said the words just came to him.
"I was standing about 50 feet behind him ... and I saw it happening in real time," Mr. Jones recently told students at Stanford University, where he is a writer in residence. "[King] just took the text of his speech and moved it to the left side of the lectern. ... And I said to somebody standing next to me: 'These people don't know it, but they're about to go to church.' "
It's a great story and a great lesson -- finding the right words is sometimes a matter of planning and sometimes sheer happenstance -- and we can only hope, for the purposes of this column at least, that it is true.
Mackenzie Carpenter: email@example.com or 412-263-1949.