Today, the Supreme Court heard oral arguments in King v. Burwell, a case with significant implications for the future of Obamacare. Most of the justices’ questions proceeded along expected lines. Most notable was a series of questions by Associate Justice Anthony Kennedy, who questioned whether it would be constitutional for Obamacare to induce states to set up exchanges. If Kennedy’s fears are right—that federal subsidies for state-based exchanges are “coercive”—then he might side with the Obama administration in the case. But if you understand how Obamacare’s insurance markets work, it’s clear that Kennedy should side with Obama’s challengers.