For the second time in a year, the Supreme Court has agreed to wade into an election case at the urging of conservatives. In both cases it has done so despite the issue appearing to be settled by long-standing precedent. In a case expected to be decided next month, Arizona State Legislature v. Arizona Independent Redistricting Commission, conservatives asked the court to bar states from using independent redistricting commissions to draw congressional lines. In a case the court agreed to hear Tuesday, Evenwel v. Abbott, conservatives asked the court to require states to draw their legislative district lines in a particular way: Rather than considering the total population in each district, conservatives argue, the lines should instead divide districts according to the number of people registered or eligible to vote. Most states use total population for drawing districts, which includes noncitizens, children, felons, and others ineligible to vote. In both Supreme Court cases, there is great irony in the fact that they are being brought by conservatives, who usually claim to respect precedents and states’ rights. The challengers are not only asking the court to revisit issues that seemed to be settled by decades-old precedent. If successful, these cases will undermine federalism by limiting states’ rights to design their own political systems.