# United States v. Microsoft (1998–2002) **Filed:** May 18, 1998 by DOJ and 20 states · D.D.C., Judge Thomas Penfield Jackson The case that established the shape of every platform monopolization case since. The government alleged §1 tying (bundling Internet Explorer with Windows) and §2 monopoly maintenance in Intel-compatible PC operating systems, protected by what Jackson called the **applications barrier to entry** — the self-reinforcing loop in which developers write for the dominant platform because users are there and users stay because the applications are. - **1999-11-05** — Findings of fact: [[Microsoft]] holds monopoly power and used it to harm consumers - **2000-04-03** — Conclusions of law: §2 monopolization *and* §1 tying - **2000-06-07** — Judgment ordering the company split into an operating-systems firm and an applications firm - **2001-06-28** — D.C. Circuit, en banc: **affirms** monopoly-maintenance liability, **vacates the breakup entirely**, remands tying for rule-of-reason analysis, and disqualifies Judge Jackson for giving press interviews - **2001-11-02 / 2002-11** — Settlement: conduct remedies only (API disclosure, OEM freedom, a technical committee), expiring 2011 Liability survived; the structural remedy did not. It was the last serious American attempt to break up a technology company until DOJ sought divestiture of Chrome in 2025 — and lost that too. The case is also the standard counterfactual for Google's rise: whatever the remedy did or didn't do, Microsoft spent the browser wars in court. > Stub — fill out. See [[US Antitrust and Monopoly Timeline]].