The Framers of the Constitution believed that they could thwart the rise of political parties by having a President and legislature who were elected completely

The Framers of the Constitution believed that they could thwart the rise of political parties by having a President and legislature who were elected completely separately and would be locked in a power struggle against each other. The pardon power is to prevent legislative overreach -- if the legislature made jaywalking a federal crime with a 10 year jail sentence, the President (or the jury) could simply refuse to allow this law to be enforced. Despite the high profile political cases, the majority of presidential pardons are given to people who have sat in jail for a long time on crimes that are not at the highest level of turpitude such as murder/rape/kidnapping.