Rule of law as institutional substrate — contract enforcement, judicial independence, equal treatment before the law. Upstream of most other axes.
Loi 99-944 of 15 November 1999 created the Pacte Civil de Solidarité, a civil-union contract open to couples of any sex, providing tax, inheritance, and social-security arrangements short of full marriage. Landmark progressive legislation; PACS unions subsequently grew to constitute a majority of new couple-registrations annually by 2010.
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.