Here's the thing. Ted Cruz is being extremely dishonest when he conveys the impression that it takes a "flat tax" to simplify taxes and "abolish the IRS".
He is also dishonest that a "flat tax" will guarantee your taxes will be simplified. It's a lie.
There are currently seven tax brackets, but even with that many you could fill out your taxes on a postcard.
What complicates the filing of taxes is not the number of tax brackets. What complicates taxes is the tens of thousands of exemptions, credits, and deductions.
You don't ever hear Ted Cruz say he would completely eliminate exemptions, credits, and deductions. And this means he would protect the favors industry that exchanges campaign cash for exemptions, credits and deductions for special interests.
Because even a "flat tax" will have exemptions, credits, and deductions unless they are specifically banned. You will still have to fill out a lot of forms to determine your eligibility for any of the thousands of exemptions, credits, or deductions.
And that means you will still need a massive IRS to handle the complexities of that system.
So don't be fooled by his bullshit that a "flat tax" will enable you to fill out your taxes on a postcard.