There’s precedent for country-wide state action over a variety of policy

Today, over two hundred interstate compacts are in operation.24 The prevalence of these compacts has boomed over the past century. Until the 1920s, states used them sparingly, mostly as a means to settle boundary disputes. But the 1922 creation of the Port Authority of New York and New Jersey—one of the most famous examples of interstate compacts—opened the door for the use of these compacts to tackle increasingly frequent and complex interstate issues.25 Since then, the number of interstate compacts exploded not only in number but in reach. Unlike the bistate agreements of the nineteenth century, many compacts today are regional, and roughly two dozen are national.26 Today, states are used to managing these arrangements: the average state is a party to twenty-five of these interstate agreements.27 The nature of compacts has expanded to cover all manner of political, social, and environmental issues. The majority of compacts established since the 1970s have served regulatory purposes, most often through the establishment of regulatory agencies.28 Recently, states have increasingly looked to interstate compacts as a more viable means of making progress on intensely partisan issues. In the face of federal inaction on tobacco, all but four states formed a compact to increase the price of cigarettes, which now yields billions in revenue each year.29 One notable success is the 2008 Regional Greenhouse Gas Initiative (RGGI), which, in response to federal inaction to curb rising emissions, created the first “mandatory, market-based CO2 emissions reduction program in the United States.”30 Under RGGI, the nine signatory states participate in a regional cap-and-trade program to limit CO2 emissions from the power sector.31 RGGI has operated for years without explicit congressional approval and has “claimed reductions in lifetime energy bills” of nearly $5 billion for 4.6 million residences.