PRE-EMPTION OF SUB-NATIONAL CONSTITUTIONAL CHOICES
Another way to minimize conflicts between federal and sub-national constitutions is to prescribe the contents of the sub-national constitutions in the federal constitution. Indeed, the federal constitution may obviate the need for sub-national constitutions altogether by mandating the form of government for sub-national units, thus creating a “complete” federal constitution, with no sub-national constitutional space.
Formerly unitary countries that have decentralized into federal systems – that is, countries that exemplify devolutionary rather than integrative federalism – may be particularly likely to include sub-national constitutional arrangements in the national constitution.28But even if a country permits the creation of sub-national constitutions external to the federal constitution, mandates in the federal constitution can restrict the range of choice for sub-national constitution makers or induce the sub-national units to alter their constitutions to bring them into conformity with national requirements.29 For example, the Brazilian Constitution mandates in detail the content of state constitutions, extending to such matters as the number of state legislators and their pay ceilings; and the Mexican Constitution prescribes a separation of powers in state government and limits state governors to a single six-year term.30 A less specific, though still important, kind of mandate is the “homogeneity clause” found in both the German and Austrian federal constitutions, which requires that the constitutional order in the länder conforms to the principles of a republican, democratic, and social state of law.31 And the Austrian Constitution further requires that länder constitutions not “affect” the federal constitution.32
In many federations, federal constitutional provisions not directly addressed to sub-national constitutions also have an indirect effect on state constitution-makers. Perhaps the most important of these is the “supremacy clause” found in most federal constitutions.
These clauses confirm that federal law is superior to state law, so that in cases of conflict, valid federal enactments – be they constitutional provisions, statutes, or administrative regulations – prevail over state enactments, including state constitutional provisions. This limits sub-national constitutional space, and it may deter sub-national constitution-makers from adopting provisions they favour. Likewise important may be the lists of competences awarded either exclusively or concurrently to the federal government. The broader the range of competences granted exclusively to the federal government, the fewer the opportunities available to sub-national units to address matters in their constitutions or statutes; while the broader the range of concurrent competences, the greater the opportunities for the federal government to occupy the field and thereby reduce sub-national policy-making.