Why were the majority of African Americans become Democrats during Franklin Roosevelt's time in office after having been Republicans before that?
I understand it was because of the New Deal but can you explain what it was about the New Deal and what it was about the Republican party before that
The reason that African Americans were mostly Republican before the New Deal goes back to the Civil War and its aftermath. President Lincoln who, of course, issued the Emancipation Proclamation was a Republican. In the years of Reconstruction, it was the Republicans who pushed for the rights of African Americans. At the same time, the white South was solidly Democratic and the Democratic Party was the party that opposed any moves towards equality for African Americans.
The New Deal changed this because it provided government help to the poor. African Americans were suffering from the Great Depression. The New Deal was something they saw as a great help to them. Because the New Deal was a Democratic idea, African Americans moved towards that party.
We should also note, however, that actions that were taken by President Roosevelt and his wife (other than the New Deal) helped to move African Americans towards the Democratic Party. Roosevelt ended some types of discrimination in government programs and appointed African Americans to some government positions. These actions were not part of the New Deal per sebut they helped to convince African Americans to move to the Democratic Party.