Ed Kilgore, writing at Washington Monthly about flat taxes and other tax schemes:
A lot of these ideas get jumbled together in politicians’ rhetoric, as Paul Waldman noted the other day at the Prospect
[A]lmost every potential GOP presidential contender has at the very least expressed support for tax flattening, and most of them have come out and endorsed a flat tax.
But the details are hazy and often contradictory. Ted Cruz, for example, has endorsed both a consumption tax and a “flat” income tax (Mike Huckabee is the one consistent consumption tax proponent). Rand Paul, Rick Perry, and Bobby Jindal have all indicated support for a flat income tax. Jeb Bush and Marco Rubio have spoken of a flat income tax as a “goal.”
The political motive for such talk, or at least so I think, is to do two things: first, it offers an alternative, less unseemly way of talking about upper-income tax rate reductions, and second, it sneakily scratches the itch of conservative “base” anger at the “lucky duckies” who are too poor to pay income taxes under the current system.
"Tax reform" rhetoric on the right is a form of dog-whistle politics that serves a few different purposes.
For the high-end constituents, it translates to "I will make it so you don't have to pay as much in taxes." As Kilgore rightly points out, for all the talk about simplification, what these schemes are really about is making sure that rich people pay less money in taxes.
For the GOP-voting masses, on the other hand, the happy-talk about simplifying the tax code speaks to their deep-seated suspicion that somewhere, somehow, some poor person (probably a minority) is getting a hand-out s/he doesn't deserve.
Either way, it is empty rhetoric, and I would bet money that the candidates and pundits who engage in it know that. We are a country of nearly 320 million people, with a complex and interconnected economic and financial system. Our tax code falls under my general rule "Complicated things are complicated." It is probably about as simple as it is going to get.