Final answer:
The subject is executive clemency, which includes pardons and commutations that governors and presidents can grant to absolve individuals from blame for crimes against the government, illustrated by historical examples like Johnson's Proclamation of Amnesty and Reconstruction.
Step-by-step explanation:
The concept described pertains to the use of executive clemency, which includes both pardons and commutations. Governors and presidents hold this power, enabling them to absolve individuals from blame for crimes against the government and potentially secure their release from prison. A famous historical example of this is President Johnson's Proclamation of Amnesty and Reconstruction in May 1865, which offered amnesty and pardon to those in the South after the Civil War, provided they affirmed their support for the U.S. Constitution.
Historically, this power has been exercised variously, from Johnson's selective amnesty to measures taken by governors to commute death sentences. Presidents like Abraham Lincoln used their pardon power to further goals of national healing and reconstruction following the war. Overall, pardons and commutations serve as key mechanisms in the executive branch's oversight of the criminal justice system.