“One person, one vote is the great equalizer of humanity.”
at LCV Annual Gala https://www.lcv.org/article_category/blog/Speech
            Writing for the court, Gray v. Sanders, 372 U.S. 368, 381 (1963) 
Judicial opinions
        
“One person, one vote is the great equalizer of humanity.”
at LCV Annual Gala https://www.lcv.org/article_category/blog/Speech
                                        
                                         Sixth Lincoln-Douglas debate https://cwcrossroads.wordpress.com/2011/01/18/race-and-slavery-north-and-south-some-logical-fallacies/#comment-47553, (13 October 1860), Quincy, Illinois 
1860s 
Context: You know that in his Charleston speech, an extract from which he has read, he declared that the negro belongs to an inferior race; is physically inferior to the white man, and should always be kept in an inferior position. I will now read to you what he said at Chicago on that point. In concluding his speech at that place, he remarked, 'My friends, I have detained you about as long as I desire to do, and I have only to say let us discard all this quibbling about this man and the other man-this race and that race, and the other race being inferior, and therefore they must be placed in an inferior position, discarding our standard that we have left us. Let us discard all these things, and unite as one people throughout this land until we shall once more stand up declaring that all men are created equal'. Thus you see, that when addressing the Chicago Abolitionists he declared that all distinctions of race must be discarded and blotted out, because the negro stood on an equal footing with the white man; that if one man said the Declaration of Independence did not mean a negro when it declared all men created equal, that another man would say that it did not mean another man; and hence we ought to discard all difference between the negro race and all other races, and declare them all created equal.
                                    
2000s, The Real Abraham Lincoln: A Debate (2002), The Right of Secession Is Not the Right of Revolution
                                        
                                         How to Think about the American Revolution: A Bicentennial Cerebration https://books.google.com/books?id=iKGGAAAAMAAJ (1978) p. 53 
Also quoted in  Vindicating the Founders https://books.google.com/books?id=DjlpSl-x1gMC, by Thomas G. West, p. 32 
1970s
                                    
1960s, Special message to Congress on the right to vote (1965)
                                        
                                        Introduction: Thinking about Politics. 
On Politics: A History of Political Thought: From Herodotus to the Present (2012)
                                    
1960s, Emancipation Proclamation Centennial Address (1962)
                                        
                                         "Politics" http://www.ingo-heinemann.de/Politik.htm (13 February 1965). 
Scientology Policy Letters
                                    
Remarks on voting rights (29 December 2003) http://www.clark04.com/speeches/024/
1870s, Message to the Senate and House of Representatives (1870)