Powers of
government that are
reserved for
states sometimes referred to as "
state's rights" (often in the context of opposition to
civil rights.) It basically gives the
individual state the right to determine its own
local government and policy on issues (
health,
safety, etc.) that fall outside of the broader definitions of
federal law. It's like
micro marketing for
legislation. The
exception to this is that
local laws cannot directly
conflict with
federal law.
A perfect example of this is Little Rock's refusal to integrate its schools which led to direct intervention (and occupation) by federal troops to make sure the law was followed.