They killed jews and a lot of other people that weren't Aryan, they imposed militarism and created a bunch of havoc in Europe and then started ww2
The judicial branch (supreme court) can declare laws unconstitutional. This is a check because the legislative branch can create laws.
The Three-Fifths Clause was one of the many compromises delegates worked out during the Constitutional Convention in 1787. It struck a balance between large slave states in the South and smaller northern states that had abolished slavery. It restricted, but not eliminated, the apportioned congressional representation of slave states by limiting the Census to counting slaves as only three-fifths of a person
