How does federalism allow for political and economic diversity among the states?

Officially, Johnson was impeached for violating the Tenure of Office Act, which had been passed over Johnson's veto, which prohibited the president from dismissing certain federal officials without Senate approval, and for denouncing Congress as unfit to legislate. But those reasons masked the issues that were more important to Congressional Republicans. Johnson had vetoed 20 Reconstruction bills and had urged southern legislatures to reject the 14th Amendment, guaranteeing equal protection of the laws. He had ordered African American families evicted from land on which they had been settled by the U.S. Army.