According to today's U.S. Supreme Court decision Harris v. Quinn, not much. Mandatory state bars, including Michigan's, were watching Harris closely (see the amicus brief submitted by 21 past presidents of the District of Columbia Bar), worried that if, as some amici urged, the court repudiated the seminal Michigan public union case Abood v. Detroit Board of Education, the decision would undermine the reasoning of Keller v. State Bar of California, the case defining what mandatory state bars are allowed to do, because Keller referred to Abood by analogy. Instead, the decision today expressly offers this reassurance to mandatory state bars:
In Keller, we considered the constitutionality of a rule applicable to all members of an “integrated” bar, i.e., “an association of attorneys in which membership and dues are required as a condition of practicing law.” 496 U.S., at 5. We held that members of this bar could not be required to pay the portion of bar dues used for political or ideological purposes but that they could be required to pay the portion of the dues used for activities connected with proposing ethical codes and disciplining bar members. Id., at 14.
This decision fits comfortably within the framework applied in the present case. Licensed attorneys are subject to detailed ethics rules, and the bar rule requiring the payment of dues was part of this regulatory scheme. The portion of the rule that we upheld served the “state’s interest in regulating the legal profession and improving the quality of legal services.” Ibid. States also have a strong interest in allocating to the members of the bar, rather than the general public, the expense of ensuring that attorneys adhere to ethical practices. Thus, our decision in this case is wholly consistent with our holding in Keller.
This language offers some comfort to supporters of the mandatory bar, given the troubling signs in Harris that Abood is on very thin ice. Prof. John Eastman, writing today in SCOTUSblog, said "One can almost see the ghoul of Abood walking ever more slowly, arms outstretched, as its legs are shot out from under it piece by piece."