One of my cherished possessions, which I cart with me around the world, is a tattered paperback copy of the Penguin Book of Twentieth-Century Speeches.
On the front cover, John F Kennedy stands gripping a lectern, in full flow; on the back, Martin Luther King raises a hand before the crowd at the Lincoln Memorial in Washington DC.
As you gaze at that second picture, you can hear his preacher's voice, resonant and rhythmic. You can hear the cadences rise and fall, a hint of vibrato, as he describes his dream.
On the pages in between, the speeches shine brightly with democratic ideals, many proclaimed by American presidents.
There is Woodrow Wilson, promoting the League of Nations in Pueblo, Colorado in September 1919: "There is one thing that the American people always rise to and extend their hand to, and that is the truth of justice and of liberty and of peace."
There is Herbert Hoover's great rallying cry for conservatism in New York in October 1928: "The march of progress" founded on "ordered liberty, freedom and equal opportunity to the individual."
The Wall Street crash of the following year brought that march to an abrupt halt, and by the spring of 1933, when Franklin Delano Roosevelt's inauguration speech crackled across the radio airwaves, the nation was in the desolation of the Great Depression.
Roosevelt's watershed inaugural is best remembered for its signature line - "the only thing we have to fear is fear itself" - but it contained much else besides, not least a warning of the "false belief that public office and high political position are to be valued only by the standards of pride of place and personal profit".
A Democrat, Roosevelt might have abjured the "rugged individualism" of his Republican predecessor, but the two presidents shared a commitment to liberty, characterised by Roosevelt in his 1941 address to Congress as "four freedoms": namely the freedoms of speech and religion and freedoms from want and fear.
"Enduring peace cannot be bought at the cost of other people's freedom," he declared.