The centrist Democrats at the Hamilton Project have a new paper on tax reform  in which they lay out six guiding principles:

1. Fiscal responsibility requires addressing both taxes and spending.
2. Rising inequality strengthens the case for progressivity.
3. The tax system should collect the taxes that are owed.
4. Tax reform should strengthen taxation at the business level.
5. Taxes for individuals should be simplified.
6. Social policy can and should often be advanced through the tax code–and it must be well designed.

I can agree with their  points 1,2,3 and 5, but No. 4 — collecting more taxes from businesses —  will be difficult in an era of global competition. And I find No. 6 particularly problematic.  

The trouble is, when we use the tax code for social engineering, the law of unintended consequences comes into play. We want to encourage home ownership, so  we make mortgage interest tax deductible — giving a huge subsidy to the millionaire, but none at all for a low-income person who either doesn’t make enough to pay taxes, or who benefits more from the standard deduction. (This particular bit of social engineering actually makes the tax code less progressive, conflicting with principle No. 2 above.)

My instinct  is that goals No. 5 (simplification) and 6 are fundamentally irreconcilable.  Most taxpayers would  be better off under a simplified  system that  reduced tax rates and  eliminated  all the deductions, credits, etc., that the social engineers have put into the tax code.