<P> In August 1963 , 22 - year old folksinger Joan Baez , led a crowd of 300,000 in singing `` We Shall Overcome '' at the Lincoln Memorial during A. Philip Randolph 's March on Washington . President Lyndon Johnson , himself a Southerner , used the phrase `` we shall overcome '' in addressing Congress on March 15 , 1965 , in a speech delivered after the violent , `` Bloody Sunday '' attacks on civil rights demonstrators during the Selma to Montgomery marches , thus legitimizing the protest movement . </P>
who validated the civil rights movement by proclaiming we shall overcome
President Lyndon Johnson