{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T15:31:24Z","timestamp":1786721484382,"version":"build-2736575974"},"posted":{"date-parts":[[2026]]},"group-title":"SSRN","reference-count":0,"publisher":"Elsevier BV","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>On February 20, 2026, the U.S. Supreme Court ruled in Learning Resources, Inc. v. Trump (607 U.S. ___) that the International Emergency Economic Powers Act does not authorize the President to impose tariffs, striking down the April 2025 Liberation Day tariffs. Using NASDAQ TotalView Level 3 data for 8 stocks across three days (pre-ruling, ruling day, post-ruling), I test whether the ruling reversed the microstructure regime shift documented during Liberation Day. It did not. Ten months after the original shock, order lifetimes have been permanently reshuffled relative to pre-Liberation Day levels, submillisecond order share remains 19% higher (31% vs 26%), and cancel-to-trade ratios remain 23% lower (8.8 vs 11.3). The Supreme Court ruling itself produced no significant microstructure reversal. These findings suggest that major policy shocks trigger permanent regime shifts in order book dynamics that persist even after the underlying policy is judicially reversed.<\/jats:p>","DOI":"10.2139\/ssrn.6562501","type":"posted-content","created":{"date-parts":[[2026,4,20]],"date-time":"2026-04-20T16:14:20Z","timestamp":1776701660000},"source":"Crossref","is-referenced-by-count":0,"title":["Did the Supreme Court Restore Order Book Normalcy? Microstructure Evidence from Learning Resources v. Trump"],"prefix":"10.2139","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-8477-9393","authenticated-orcid":true,"given":"Boon Chuan","family":"Lim","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"78","container-title":[],"original-title":[],"deposited":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T14:45:30Z","timestamp":1786718730000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ssrn.com\/abstract=6562501"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026]]},"references-count":0,"URL":"https:\/\/doi.org\/10.2139\/ssrn.6562501","relation":{},"subject":[],"published":{"date-parts":[[2026]]},"subtype":"preprint"}}