Because it was a union stronghold in the confederate states.
If there is a 2/3 vote the veto is appealed and it becomes law
B) Radical Republicans thought Johnson was too harsh toward the South.
Johnson's refusal to support the legislation that had united the Republican majority in Congress proved fatal to his program, for it had driven the moderates into the Radical camp. ... By passing the Civil Rights Bill, the Republicans had shown their commitment to civil rights for blacks.
Answer:
I am going to guess radios, newspapers, and new beliefs of the presidential nominees helped.
Explanation: