In District of Columbia v. Heller, Justices Stevens and Breyer wrote lengthy dissents (46 pages and 44 pages, respectively) from Justice Scalia’s majority opinion. Stevens and Breyer joined each other’s dissent, and Ginsburg and Souter joined both.
I’ve barely had time to skim the dissents, so I’ll provide only a very high-level summary.
Stevens doesn’t dispute that the Second Amendment protects an individual right, but he finds the scope of that right limited to using weapons for certain military purposes. He argues that the text of the Second Amendment (5-17), its drafting history (17-27), and the Court’s precedents—especially its 1939 ruling in United States v. Miller (42-45)—support his reading.
Breyer argues that even if the Second Amendment does protect a right of personal self-defense, D.C.’s law is constitutional because the burdens it imposes are not disproportionate in light of the law’s legitimate objectives. (That sure sounds like a meaningful test, doesn’t it?)