You needed Caplin & Drysdale to confirm? How about a simpler example: firms prepay expenses in 2020 for goods/services in early 2021. Expenses deducted at 35%, income associated with goods/services taxed at 21%. We've seen this movie before. https://tpc.io/2AJuCC3  https://twitter.com/ScottElliotG/status/1262432074012798978

For the tax geeks who object: how can a firm deduct without "economic performance"? Firms can deduct payments for services or property that will be provided within 3 and 1/2 months after the date of payment (in the following tax year). Treas. reg. sec. 1.461(d)(6)(ii).