Constitutions are treated as founding documents and function as working allocations of authority, and the relationship between the text and the actual arrangement varies considerably.
The functions
Establishing institutions and defining their powers.
Allocating authority between levels of government.
Setting out the process for making law.
Constraining what government may do, generally through rights provisions.
And specifying how the constitution itself may be changed.
Written and unwritten
Most countries have a single codified document.
Some operate through a combination of statutes, court decisions, conventions and practice without a single text.
Which is not the absence of a constitution but a different form of one, and it means constitutional change can occur through ordinary legislation.
Conventions
Rules that are not legally enforceable and are followed consistently.
Which do enormous work in several systems — how a head of state exercises formal powers, how governments are formed, when officials resign.
They depend on being observed, which means they constrain only actors who accept them.
Codifying conventions has been proposed periodically and would change their character by making them justiciable.
Rigidity
Amendment procedures vary enormously in difficulty.
Some require supermajorities in multiple bodies plus ratification by subunits, which makes formal amendment very rare.
Others can be amended by ordinary legislative majority.
Which affects how change occurs — rigid constitutions change through judicial interpretation rather than through amendment, since that is the available route.
Rights provisions
Generally include civil and political rights, and increasingly economic and social rights in more recently written constitutions.
Which raises the question of justiciability — whether a right to housing or health can be enforced by courts.
Some systems treat these as directive principles guiding policy rather than as enforceable rights.
Others have enforced them, with courts ordering government action, which has generated substantial debate about institutional competence.
Emergency provisions
Most constitutions permit suspension of certain protections during declared emergencies.
Which is where the risk of abuse concentrates, and safeguards typically include time limits, legislative approval and non-derogable rights that cannot be suspended.
Comparative research on emergency powers finds that extended states of emergency are associated with democratic erosion.
Constitutional courts
Bodies specifically constituted to rule on constitutional questions, existing in many systems.
Which differ from ordinary supreme courts in composition, appointment and jurisdiction.
Their independence is a recurring point of political conflict, since they constrain governments.
The gap between text and practice
Constitutions can guarantee rights that are not respected, and can be silent about arrangements that operate reliably.
Which means comparative assessment uses practice rather than text.
Projects coding constitutional provisions and comparing them with measured outcomes find the relationship is real and far from deterministic.
Judicial appointment and court packing
Changing court size or composition to alter outcomes.
Which has occurred in several countries and is a recognised indicator in comparative research on democratic erosion.
Constitutional entrenchment of court size prevents it in some systems and not others.
Referendums
Used for constitutional change in many systems, either as a requirement or as an option.
Which raises questions about thresholds, question wording and the role of legislatures in framing choices.
Comparative research on referendum design examines how these choices affect outcomes and legitimacy.
Constitutional interpretation
Approaches differ substantially, from emphasis on original meaning to treatment of the text as adapting over time.
Which produces different outcomes from identical text, and the choice of approach is itself contested and consequential.
Judicial appointment fights frequently concern interpretive philosophy rather than views on specific issues.
Federalism and unitary systems
Constitutions establish whether power is divided territorially or held centrally with delegation.
Which is among the most consequential structural choices, and it is difficult to change subsequently.
Devolution within unitary systems creates arrangements resembling federalism without constitutional entrenchment, meaning powers can be withdrawn.
Constitutional moments
New constitutions are generally written following crisis, transition or independence.
Which means the drafting context shapes the document, and provisions frequently address the specific failure that preceded it.
Participatory drafting processes have been used increasingly, with evidence that inclusive processes produce more durable constitutions.
Reading it
Constitutional texts are published and are generally short.
Which makes reading the relevant provisions directly practical, and comparative databases allow provisions to be compared across countries.
Understanding what a system's constitution actually says is a reasonable foundation for assessing claims about it.
Amendment in practice
Some constitutions have been amended frequently and others almost never.
Which reflects the procedure and the political culture, and comparative data on amendment rates is published.
Rigid constitutions accumulate pressure that finds other outlets, generally judicial interpretation.
Durability
Comparative research finds median constitutional lifespans considerably shorter than most people assume, with many replaced within decades.
Which is associated with factors including inclusiveness of the drafting process, specificity of provisions and flexibility of amendment.
Highly detailed constitutions have shorter average lifespans, since more provisions become obsolete.