On January 11, 2011, the Supreme Court decided Mayo Foundation for Medical Education and Research v. United States, in which it definitively settled on the more deferential Chevron standard for analyzing Treasury Department regulations, finding no justification in treating them differently from regulations of other agencies. In doing so, the Court has given the Treasury Department virtually free rein in crafting new regulations and amending those regulations already in existence. Because taxpayer lawsuits were one of the few ways in which Treasury regulations could be overturned, by instructing the lower to give such regulations the heightened degree of deference that Chevron prescribes, the Court has greatly reduced the likelihood that these taxpayer suits will be successful.
Daniel W. Graves,
Not So Special after All: How Mayo Granted the Treasury Unfettered Rule-Making Discretion,
77 Mo. L. Rev.
Available at: https://scholarship.law.missouri.edu/mlr/vol77/iss1/11