Obama's Speech at Selma, 2015'' In this passage, President Obama uses allusion for what purpose?

President Obama uses allusion in his speech at Selma in 2015 to draw upon the historical significance of the civil rights movement and the struggles and sacrifices made by those who fought for equality. By referencing key events and figures from this period, he is able to connect the past to the present and highlight the progress that has been made while acknowledging the work that still needs to be done to achieve true equality. The use of allusion helps to create a sense of unity and shared history among his audience and emphasizes the continuing importance of the fight for civil rights.