Rule of law as institutional substrate — contract enforcement, judicial independence, equal treatment before the law. Upstream of most other axes.
Civil Union Act 2004 (Royal Assent 13 December 2004, operative 26 April 2005) recognised same-sex and opposite-sex civil unions with rights substantially equivalent to marriage. Passed 65-55 conscience vote. Paired with Relationships (Statutory References) Act 2005. Precursor to 2013 Marriage (Definition of Marriage) Amendment Act.
Per invariant 3, reforms are scored by what they did on each channel-separated axis, not by the party that enacted them. This fingerprint is how the policy-match engine finds historical analogues.
Explicit links are curated by the author. Inferred links are hypotheses in the library that test the same axes this policy moved — the framework's answer to "what does the data say about a policy like this?".
Ranked by axis-fingerprint overlap with this policy. Direction match bolded — those are the closest historical analogues. Shape of the match is what drives policy-outcome comparison, not the country or party label.