The major advantage is that the states have their own right to choose which laws will apply to them and in what way, based on their own interpretation of the laws.
this is what i found if this not help im sorry and i qote
"The purpose of this study is to assess the ways in which President Dwight D. Eisenhower and John F. Kennedy reacted to the civil rights crises in Little Rock in 1957 and at Ole Miss in 1962. A side theme is to assess presidential learning by seeing whet Kennedy learned from the lessons taught by Eisenhower. Each president was reluctant to commit federal troops to enforcing civil rights, was concerned about the problems associated with federalism, and ended up feeling forced to commit troops nonetheless. The message is that despite the presidents' best intentions, troops ultimately had to be committed. Kennedy was unable to avoid the traps that Eisenhower had encountered, and the imposition of the national government on the enforcement of civil rights was firmly established.
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B. the electoral college etc
