Rule of law as institutional substrate — contract enforcement, judicial independence, equal treatment before the law. Upstream of most other axes.
General government spending as share of GDP, excluding transfers already captured under fiscal.transfer_expansion to avoid double-counting.
Three constitutional-revision stages delivering Belgian federalisation: 1980 (communities with cultural/educational competences); 1988-89 (regional governments with economic/ employment competences); 1993 (Article 1 Constitution redefining Belgium as federal state, St Michael Accord creating Brussels region and Flemish/French community structures). Institutional transformation spanning Martens era and completed under Dehaene.
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.