Answer:
The Eighth Amendment
Explanation:
The Constitution's Eighth Amendment prohibits the federal government from imposing excessive bail, excessive fines, or cruel and unusual punishment.
Tangent:
There is an interesting caveat to this, outlined by 1977 Supreme Court case Ingraham v Wright, where Florida's public schools maintained the right to use corporal punishment (physical pain) for disciplining or punishing its students.
14 year-old James Ingraham didn't listen to his teachers, was sent to the office, insisted he was innocent, and was promptly spanked with a paddle, suffering injuries that required medical attention. The Supreme Court found that this wasn't a violation of the 8th Amendment, and his case can be handled in lower level courts.
