Originally, the US Bill of Rights did not apply at the state level; only the federal level. For instance, the right for a criminal to be represented by counsel, granted by the 6th Amendment, did not originally apply to state level criminals.
The process of incorporation of the Bill of Rights reversed this and made these rights apply to state level. But why wasn't it this way to begin with? What was the original rationale to have the Bill of Rights only apply to the federal level?
Barron v. Baltimore 2 U.S. 243 (1833) explains the rationale:
The Constitution was ordained and established by the people of the United States for themselves, for their own government, and not for the government of individual States. Each State established a constitution for itself, and in that constitution provided such limitations and restrictions on the powers of its particular government as its judgment dictated. The people of the United States framed such a government for the United States as they supposed best adapted to their situation, and best calculated to promote their interests. The powers they conferred on this government were to be exercised by itself, and the limitations on power, if expressed in general terms, are naturally and necessarily applicable to the government created by the instrument. They are limitations of power granted in the instrument itself, not of distinct governments framed by different persons and for different purposes.
