Vice President Biden has just proposed a 15% corporate minimum tax based on companies' financial statement accounting income (aka, book income) above a large threshold. By contrast, Senator Warren is proposing a 7% add-on or additional tax on book income above the threshold. The difference is that the latter would be payable in all events, while the former would be payable only to the extent in excess of regular taxable income (albeit, with multi-year smoothing provisions).
Leaving aside perhaps the biggest issue here, which pertains to taxing book income or not, the contrast between them raises the classic old issue of minimum taxes versus separate add-on taxes. I have begin writing about this issue more generally (including in my analysis the US experience with the individual and corporate AMTS, as well as global minimum taxes such as GILTI and the OECD Pillar Two Globe proposal. But it also goes way back for me. The first article I published after entering academe in 1987 was entitled something like "Perception, Reality, and Strategy: The New Alternative Minimum Tax." I published it in Taxes Magazine so I could get it out fast, although in style and substance it was more like a Tax Law Review article.
I am not, however, writing the new article within a time frame that's aimed at participating in the current Democratic campaign debate. I'm more interested in getting a general analysis out there that I think is presently lacking, although lots of experts have a decent grasp on some of the main points.