The Idea That Divides a Court

Montesquieu argued that liberty is lost the moment one person or body holds legislative and executive power together.

His argument became the doctrine of separation of powers, applied with very different strictness in the United States and the United Kingdom.

The Supreme Court of Canada, final word on the Canadian Charter of Rights and Freedoms since 1949.

R v Oakes, a small drug-possession case, produced the two-part test every Charter-limiting law must now pass.

That test is Canada's own strand of a wider doctrine: proportionality, developed independently in Germany and at the European Court of Human Rights.

The High Court of Australia, apex of a federation whose constitution divides power between six states and the Commonwealth.

Commonwealth v Tasmania let a single treaty obligation override a state government's own development plans.

The Permanent Court of Arbitration, not a standing bench but a framework for tribunals convened case by case.

In 2016 one such tribunal rejected China's nine-dash line, a ruling China has never accepted.

And behind every one of these rulings sits the unresolved question this trail closes on: should a court read a text as its framers understood it, or as each generation needs it to mean.