Journalists sued for defamation may refuse to reveal their anonymous sources. To escape liability under the traditional English rule, they then need to show proof that the news is correct. By contrast, many US states have switched the burden of proof such that plaintiffs must first present evidence that the news is false. Focusing on the incentives of sources to leak, we find that the American rule reduces the frequency of type I errors (true stories are not learned by the society) at the expense of a higher frequency of type II errors (the society believes wrong stories). The American rule is superior when courts are likely to find the truth without knowing the identity of sources, and when firms can severely punish even honest sources. Furthermore, when courts rule that sources must be revealed, they should ensure a higher compliance rate of journalists under the American rule.