flat-tax also increase inequalities:
1000$ a month with a 20% tax: you already have difficulty to pay for your food, goods, appartment
10000$ a month with a 20% tax: you have no difficulty to live
In some countries, you have a progressive system:
poor : no tax
lower class: small percentage
midle : normal
high: high percentage
So everyone can live without being strangled.
Take a look at poverty rate in some liberal countries with the flat-tax.
well, if loopholes and tax havens are stopped, that would make it a different story. there's no point in taxing people who make under 20k though, they are just going to need government assistance.