The Brady Campaign has spent years trying to convince the courts to strike down a federal law, passed with bipartisan support, that bans suits against gun makers for acts committed by criminals. It has spent great effort to get judges to override a popular law, under a novel "separation of powers" argument. But yesterday, its head, Paul Helmke, wailed about "judicial activism" that supposedly overrides "the will of the people" in an editorial in the Atlanta Journal. His complaint is like the pot calling the kettle black. The reason for his wailing is that the D.C. Circuit Court of Appeals struck down Washington, D.C.'s handgun ban, citing the Second Amendment "right to keep and bear arms." Whatever you may think of the D.C. Circuit's decision, it is based on a plausible interpretation of the Constitution's text. The same can't be said for the Brady Campaign's bogus claim that the federal law that protects gun-makers violates the "separation of powers" -- an erroneous interpretation of an amorphous concept that isn't even mentioned in the Constitution's text, but whose existence is reflected in specific constitutional provisions, like the Appointments Clause, that prevent conflict between branches of government, and limit the diffusion of government power. The Brady Campaign claims that the federal law limiting gun lawsuits (known as the Protection of Lawful Commerce in Arms Act (PLCAA)) violates "the separation of powers" because it affected pending cases against gun manufacturers, supposedly infringing on judicial prerogatives. So what? Legislatures change the law in ways that affect pending cases all the time. The classic example was the Civil Rights Act of 1964. It contained provisions that abated pending criminal prosecutions against people who engaged in sit-ins, even if the sit-ins technically violated state laws against trespassing. The Supreme Court did just that in Hamm v. City of Rock Hill (1964), overturning many convictions and dismissing many prosecutions, even though that affected pending cases. Federal laws often preempt state law. David Boaz of the Cato Institute discusses the broader implications of Helmke's argument.