Federalism complicates guarantees of personal rights through the 5th Amendment : "No person shall be held to answer for a capital...or infamous crime, unless...indictment of a grand jury..." which would apparently create a split between state or local crimes vis a vis federal or national crime law. The 14th amendment and various Supreme Court rulings addressed this complication by stating that :"No state shall deprive any person of life, liberty or property, without due process of law". Supreme Court interpreted that no state can deny anyone of rights basic to american liberty.
Federalism complicated the guarantee of personal rights because Federalism created two types of government, state, and federal government and for a long time there was confusion which one should respect personal rights.
The 14th Amendment was one of the Reconstruction Amendments and granted citizenship rights and equal protection to former slaves. This Amendment was the center of various discussions because for a long time there was a belief that only the federal government should respect it not the states governments.
Over time the Supreme Court of the US has ruled that both federal and state government have to guarantee personal rights in a process called incorporation.
