Congress will say no.

II. Can States Preempt Federal Preemption with Poison Pills?

Assume for now that the baseline question has been settled, and we are agreed that there is too much preemption. Let us turn instead to the heart of Mikos's proposal and ask whether the PPP would achieve his end of promoting a larger freedom for state regulation, which in turn would yield a more desirable regulatory regime "from a welfarist perspective." 64 As much as I admire the innovation and thought underwriting the PPP proposal, I will develop three grounds for concern. All three take up, in different ways, questions of where and how Coasean bargaining over regulatory entitlements occur. These concerns set the stage for a reconsideration of when institutional bargaining can or cannot succeed in Part III.

A. Timing and Coordinating PPPs

My first pair of concerns are surfaced by asking where "the state can trade its entitlement not to pass or enforce a law for Congress's entitlement to preempt state law." 65 Mikos identifies two potential forums. First, such deals would be reached in Congress, 66 and second, PPPs could inflect judicial constructions of the preemptive shadows of federal legislation. 67 (What about federal agencies? Mikos does not flag them as promising forums, although he briefly touches on state bargaining with the Justice Department. 68 I will come back to their potential in a moment). The first two reasons for resisting PPPs relate respectively to the timing and coordination obstacles to legislative dealmaking, and to judicial consideration. In contradistinction to Mikos's focus on the realization of Coasean deals, they both dwell on the possibility of derailing transaction costs. 69

Focus first on how PPPs would play out in the environment of legislative negotiations. 70 Imagine a potentially successful congressional coalition seeking to enact a federal statute with preemptive effect. To influence that law, state legislatures must be aware of the measure, and be capable of forming a timely response. But I am not sure it is plausible to assume that states are consistently aware of the consequences of preemptive language in federal bills, especially if such effect is implied rather than express. Scholars have expressed concern that even unfunded federal mandates fail to catch states' attention, and states' opposition to such burdens founder even though there is a federal statute that enables members of Congress to raise alarms about some fiscal spillovers. 71 Unlike unfunded mandates, preemption does not trigger special legislative-process rules. Hence, it seems reasonable to infer that the identification of preemptive legislation somewhere in the mass of federal legislation enacted each year will be a costly and difficult enterprise. If states are represented by a powerful and well-connected lobby, with ample connections to Representatives' and Senators' offices, that might flag forthcoming preemptive measures, this might not be a great concern. But if you are skeptical of the strength of the intergovernmental lobby--as Mikos professes to be 72 --you should also be leery of the idea that states will be able to anticipate regulatory threats far down the congressional pike.

This identification issue, though, is perhaps the most trivial of the barriers to effective bargaining over PPPs. There is also a timing problem that is of substantial concern. Many state legislatures have brief annual sessions. 73 They are as a result not set up either to monitor constantly what happens in Washington, or to respond in an expeditious fashion.

Even more worryingly, coalitions of states with varying concerns over different sorts of federal preemption face impressive coordination problems. States have a variety of regulatory priorities. Officials in some states care deeply about drug safety. 74 Others, by contrast, are preoccupied by the costs of federal immigration enforcement levels. 75 Differences in regulatory priorities from state to state are compounded by the fact that some federal regulation is enacted at the behest of state coalitions in order to mitigate adverse spillovers from other states' policy choices 76 (or, more sinisterly, to preserve anticompetitive advantages 77 ). Where concern for interstate spillovers fuels federal legislative intervention, it is inevitable that states will sharply disagree about the scope of needful preemption. Without some robust institutional structure through which states coordinate and resolve these motivational conflicts--which, again, Mikos has dismissed as implausible 78 --how is the bargaining with Congress that PPPs are supposedly enabling to get off the ground?

The same worry emerges when we flip our perspective to focus on how Congress would respond to PPPs. To get Mikos's model of Coasean bargaining off the ground, we have to assume federal legislators (or their staff) first know about PPPs. 79 We must further assume they object to PPPs' practical effects, rather than being indifferent 80 or welcoming them. The latter is not a safe assumption given sharp divisions today among legislators over whether specific cooperative federalism programs are appropriate. Imagine here, for example, current House Speaker Paul Ryan's response to a state threat to stop implementing Obamacare. Finally, we must assume that Congress as a body is capable of aggregating the effects of different states' PPPs--which might tether different preemption measures to a variety of cooperative federalism programs--so as to reach a rational, even accurate result. 81 Depending on the extent of one's skepticism about the contemporary Congress's rationality and epistemic capabilities, this assumption might seem, at best, demanding and, at worst, absurd.