Michigan constitution
Article IX
Section 29

The state is hereby prohibited from reducing the state financed proportion of the
necessary costs of any existing activity or service required of units of Local Government by
state law. A new activity or service or an increase in the level of any activity or service beyond
that required by existing law shall not be required by the legislature or any state agency of
units of Local Government, unless a state appropriation is made and disbursed to pay the unit
of Local Government for any necessary increased costs. The provision of this section shall not
apply to costs incurred pursuant to Article VI, Section 18.