After the White House quantum summit, I tested the claim that America built "every layer of the quantum stack." Eight layers. Named researchers. Primary sources. Quick scorecard: The PQC algorithms (ML-KEM, ML-DSA, SLH-DSA) that NIST standardized and that EO 14412 mandates for federal systems? Designed almost entirely by Europeans and Canadians. CWI (Netherlands), Bochum (Germany), IBM Zurich (Switzerland), ENS Lyon (France), Waterloo (Canada). NIST ran the process — that's a real institutional win. But the algorithmic content is international. The enabling infrastructure is even more striking. Dilution refrigerators from Finland (Bluefors) and UK (Oxford Instruments) dominate the market that cools US superconducting quantum computers. Domestic manufacturing exists (Maybell in Denver, Bluefors's Syracuse operation) but the US remains substantially dependent on European-headquartered suppliers. Control electronics from Switzerland (Zurich Instruments), Israel (Quantum Machines), Germany (Rohde & Schwarz). The CHIPS Act quantum investments are partly a response to these dependencies. On the science side: Josephson junction predicted at Cambridge (1962). First superconducting qubit demonstrated at NEC Japan (1999). Surface code traces to Kitaev (Russia). Steane code from Oxford. qLDPC codes from French and Russian mathematicians. The US built the strongest commercial integration and scaling layer. That is a real and hard-won capability. It is not the same as sole authorship of the entire stack. Policy implication: "we built everything" leads to different supply chain decisions than "we built the best integration layer, and it depends on allied supply chains." The second framing is more accurate and produces better policy. Full article with every claim sourced: https://postquantum.com/quantum-sovereignty/who-built-the-quantum-stack/ #quantum #PQC #infosec #cryptography #postquantum #supplysecurity #quantumcomputing #cybersecurity