Commercial-Law
The UCC operates under the law merchant, not the common law
Examining the movement claim that modern commercial law — the UCC, descended from the law merchant — is the controlling primary law for commercial transactions, with common-law contract relegated to a subordinate supplement. Properly disambiguated and cabined to the Code's scope, the claim holds: the UCC's own text makes it primary, and the rules of its commercial core are law-merchant-derived, not common-law-contract-derived. The overreach is the leap from there to 'all law is commercial.'
Law Merchant (Lex Mercatoria)
The body of customary commercial law that grew out of medieval European trading fairs, was administered by merchant courts, and was absorbed into the common law and later codified — surviving in the modern Uniform Commercial Code, which names it by its own terms as a supplementary source. A real and recognized legal tradition; the question Adverse Review presses is how much of the modern commercial system it actually governs.