The non-deductibility of imports is simply crazy. It will immediately increase inflation. Take IKEA, for example, they cannot source locally, they will increase prices immediately by 20%, or whatever the tax will be. At all effects, it is a flat tariff of 20% on every import. This guy seems to want to transform the US into North Korea. And think about the distortions: Boeing will become a purchasing company, making more money using the tax-credit to buy prosciutto and Camembert to sell to retailers at prices lower than the marginal cost, than producing planes.
That is Coasean reasoning from Massimo, there are other good comments as well. For instance Bob noted:
There will be a huge move to asset based leasing. So Wal-mart, instead of borrowing money will sell thier real estate to a REIT and lease it back. They essentially can keep the deduction.