A few years ago, Eric Holder, Kamala Harris and other attorneys general sparked a heated debate over whether an attorney general has a duty to defend the constitutionality of laws even when they believe those laws to be unconstitutional. Harris refused, for example, to defend the constitutionality of California’s Proposition 8, which meant that the initiative’s supporters were forced to do so themselves. That ultimately failed when the United States Supreme Court ruled that they lacked standing to do so in federal courts (although, of course, they could do so in state court, where federal standing rules do not apply). Some, including Indiana Attorney General Gregory Zoeller, denounced this refusal as a threat to the rule of law. But in my view, not only is an attorney general entirely free to refuse to defend a law she thinks unconstitutional, but she is obligated to do so.