Writing a constitution is a messy business for new or transformed states. In creating the US legislative upper house (senate), small states were given a platform to defend themselves against the heavily populated powerhouse states in the northeast. This attempt to balance regional power has instead meant disproportionate power that is undemocratic.
The 2005 Iraq constitution attempted to temper the inherent tribal conflict between the country’s 3 ethnic/religious groups (Shia/Sunni/Kurds). It failed.
How much political power should be concentrated in a central government versus distributed among regions is a perennial constitutional dilemma. This is the single greatest source of ongoing political conflict.
In Spain, separatists have waged an intermittent campaign of terror for an autonomous Basque state. Canada has a perpetual constitutional tension between French-speaking Quebec and the Anglo rest of the country. Long-simmering Scottish nationalism has flared in the wake of Britain’s doltish exit from the European Union, which England supported but Scotland did not.
Central versus local control is dealt with constitutionally by deciding upon a unitary or federal state. A unitary state is one in which regional bodies are readily overruled by the central government, which indisputably has ultimate power.
By contrast, regional governments have distinct delineated powers in a federal state. The 2 governments – federal and regional – rule with regard to different political issues.
Worldwide, only 20 states are federal systems. The rest – over 170 – are unitary.
Federation is typically found in larger states where regions have conflicting interests. Such was the case in the US between southern states reliant on slavery and northern states with residual moral repugnance to it.
Though the 20 federal systems are only 10% of the world’s states, 38% of the world’s people live in them, and they cover 49% of Earth’s landmass.
Germany has a federation that generally works well. In contrast, provincial political power has eroded in the American federal system to the point of governance bearing only a bastardized resemblance of the constitution.
Many informal arrangements alter the centralizing tendency of unitary states and power devolution in federal systems. As always, money makes a difference. Distribution of revenues (tax collection) goes a long way in determining effective power.
Tradition also plays. Both France and Britain are unitary states where the central government garners most of the revenue (76% in France; 91% in Britain).
In the UK, the central government traditionally keeps loose control over local government spending and actions. Wales and Scotland have extensive autonomy on spending within their borders, even though revenues technically belong to the central government.
Conversely, for centuries French power has been firmly lodged in Paris. In 1981, President François Mitterrand instituted several decentralizing reforms, but the French political system remains strongly centralized.
Large and diverse states often loosen the leash of centralization to flexibly meet local needs. Still, the economic desirability of uniformity has mean that most industrialized states in the world are largely centralized when it comes to regulation of commerce.