The Supreme Court declined to hear a legal challenge to San Francisco's handgun regulations on Monday, letting stand a lower court ruling upholding the rules. To court-watchers, the punt was unsurprising. Although the conservative justices declared that the Second Amendment protects an individual right to bear arms in 2008—and forbade states from infringing upon that right in 2010—the court has consistently refused to expand the scope of the Second Amendment since then. Although the lower courts are severely split on how stringently states can regulate firearms, the justices have simply refused to address the question for five years.
But on Monday, Justices Clarence Thomas and Antonin Scalia decided they'd had enough. When the court swatted away the San Francisco lawsuit, Thomas (joined by Scalia) penned a furious dissent, asserting that the time had come for the court to clearly define the scope of the Second Amendment. The justices implied that San Francisco's requirement that guns be "stored in a locked container or disabled with a trigger lock" violated the right to bear arms. (This rule is largely designed to prevent children from accidentally shooting themselves or others.) To Justices Thomas and Scalia, the regulation "burdens the core of the Second Amendment right" by slightly delaying an individual's ability to access her gun.
Any four justices can force the court to hear a case, meaning Thomas and Scalia needed only two more justices to take on the San Francisco law. Where were the other gun-friendly votes? As Adam Winkler explained in Slate last year, they may be nervous about (who else?) Justice Anthony Kennedy. Although Kennedy joined the conservatives in the previous gun cases, he is rumored to have pushed the court to add language permitting moderate gun control. Since then, Kennedy has sided with the liberals in several gun-related cases that avoided the Second Amendment question.
Thomas and Scalia aren't particularly strategic voters—but Chief Justice John Roberts certainly is. And he may prefer to let the gun issue slosh around in the lower courts rather than take a gamble and let Kennedy roll back these newly discovered Second Amendment rights.