On 15 March 1965 , United States President Lyndon B. Johnson, who had assumed the presidency after the assassination of John F. Kennedy, used the phrase “we shall overcome” in a speech delivered after the violent attacks on Civil Rights demonstrators during the 1965 march from Selma to Montgomery in Alabama, led by Martin Luther King.
In that speech to a joint session of Congress, the president outlined the deceitful ways in which election officials denied African-American citizens the vote. He said: “It is the effort of American Negroes to secure for themselves the full blessings of American life. Their struggle must be our cause, too, because it’s not just Negroes, but really, it’s all of us who must overcome the crippling legacy of bigotry and injustice. And we shall overcome.”
He was supporting the Voting Rights Act, which prohibited racial discrimination in voting, by overcoming the legal barriers that prevented African Americans from exercising their right to vote