On Monday, the court agreed with Gilbride in a concise, unanimous opinion by Justice Elena Kagan. The FAA, Kagan wrote, doesn't favor arbitration, but simply puts it "on equal footing with other contracts." If an "ordinary procedural rule" prevents "enforcement of an arbitration contract, then so be it. The federal policy is about treating arbitration contracts like all others, not about fostering arbitration." Courts may not create "custom-made rules" to "tilt the playing field in favor of (or against) arbitration."

It's pretty extraordinary to see these words in a (unanimous!) opinion from this Supreme Court. The truth is that previous arbitration precedents do have loose language discussing a "liberal federal policy favoring arbitration," which lower courts have expanded to mean "corporations always win." But Gilbride convinced the justices to walk back this rhetoric by interpreting it as an "equal-treatment principle." In doing so, they abolished pro-arbitration rules in nine different circuit courts that cover most of the country--a "sea change" in the law, as Justice Sam Alito put it during oral arguments.

Why were all nine justices so receptive to Gilbride's advocacy? The likely answer is that SCOTUS' entire arbitration jurisprudence is built on an egregiously atextual and ahistorical reading of the FAA. Whether you look at the plain text of the law or the congressional intent behind it, it's impossible to justify the court's massive expansion of mandatory arbitration. Savvy progressive litigators can occasionally exploit this foundation of sand, centering real text and history to limit the damage of indefensible precedents.