Answer:
His veto of the Civil Rights Act of 1866
Explanation:
The Radical Republicans in Congress were angered by Johnson's actions. They refused to allow Southern representatives and senators to take their seats in Congress. In 1866, the Congress passed the Civil Rights Bill, which granted African Americans equal protection under the law with whites. The Congress also renewed the Freedmen's Bureau in 1866. President Johnson vetoed both of these bills, but the Congress overturned both vetoes. Following the congressional elections of 1866, the Republican Party controlled more than two-thirds of the seats in both houses of Congress. As a result of the Republican election victory, the Congress now dictated how the reconstruction of the Union would proceed.
The first action the Republican majority took was to enact the First Reconstruction Act, in spite of Johnson's veto
