Rick Santorum is the latest Republican presidential candidate to release a plan to cut taxes. One common theme of nearly all the candidates’ plans is that they let businesses write off the cost of investments as soon as it’s incurred, and eliminate the deduction for interest paid by businesses. They achieve these results in various ways, but nine of the candidates get there: Bush, Christie, Gilmore, Huckabee, Jindal, Pataki, Paul, Rubio, and Santorum. The Tax Foundation and Americans for Tax Reform have long championed these reforms, but I’ve never before seen this degree of support for it among Republicans. Some background on the issue here.