Isn't the converse that it provides protection for the people against unfair / unconstitutional laws being enacted by states? Like the slavery issue it was - AFAIK - created to address?
Speaking from the laymans perspective of a Scot, of course.
Oh, and on the subject of taxes & spending. My position is that the state has a responsibility to provide things which an individual cannot themselves be expected to provide, but which are needed to live to an ecceptable civillized standard (note this definition is kind of the key thing that'd differ between people); to me that means policing, healthcare (including, for example, protective food and hygience regulations), defense, protection (i.e. licensing of drivers, firearms, control of airpaths, etc - stuff to minimise the danger from people doing 'dangerous' things they aren't competent to), fire protection, environmental protection (i.e. because keeping a clean environment also impacts public health and thus the workers forming an economy) and support for working (that includes support systems for the unemployed or unemployable - i.e. disabled - as well as basic public transportation and legal protections).
