More than 30 years ago, Congress identified what it said was a grave threat to the promise of equal justice for all: Federal judges were giving wildly different punishments to defendants for the same crimes. Some lawmakers feared lenient judges were giving criminals too little time in prison. Others suspected African Americans were being unfairly sentenced to steeper prison terms than white defendants. In 1984, Congress created the U.S. Sentencing Commission. The panel would set firm punishment rules, called “guidelines,” for every offense. The measure largely stripped federal judges of their sentencing powers; they were now to use a chart to decide penalties for each conviction.
Five years later, a legal challenge to the commission wound up before the U.S. Supreme Court. In Mistretta v. U.S., the court upheld the sentencing commission, saying it was needed to end the widespread and “shameful” sentencing disparities produced by the biases of individual judges. Mistretta was a momentous decision, but it’s now clear the high court relied on evidence that was flimsy and even flat-out wrong, ProPublica reports. The justices cited a single congressional report in concluding that there were disturbing and unacceptable sentencing disparities. That report was based primarily on two flawed studies from the 1970s. One was a survey of federal judges about sentences they might give in hypothetical cases. The survey ignored a basic fact about courts’ real-life workings: Judges acted as the sole arbiter of sentences in a tiny fraction of cases. The vast majority of sentences were the result of plea bargains negotiated by prosecutors and defense lawyers. There was no evidence offered that judges were signing off on vastly different plea bargain terms. Later research would debunk the claim.