The rich should pay more taxes, because the rich get more from the government.
For more than a century it's been generally recognized that the best taxes are progressive-- that is, proportionate to income.
Lately, however, it's become fashionable to question this. Various Republican leaders have trotted out the idea of a flat tax, meaning a fixed percentage of income tax levied on everyone. And in their hearts they may be anxious to emulate Maggie Thatcher's poll tax-- a single amount that everyone must pay.
Isn't that more fair? Shouldn't everyone pay the same amount?
In a word-- no. It's not more fair; it's appallingly unfair. Why? The rich should pay more taxes, because the rich get more from the government.
Consider defense, for example, which makes up 50% of the budget. Defending the country benefits everyone; but it benefits the rich more, because they have more to defend. It's the same principle as insurance: if you have a bigger house or a fancier car, you pay more to insure it.
Investments in the nation's infrastructure-- transportation, education, research & development, energy, police subsidies, the courts, etc.-- again are more useful the more you have. The interstates and airports benefit interstate commerce and people who can travel, not ghetto dwellers. Energy is used disproportionately by the rich and by industry.
As for public education, the better public schools are the ones attended by the moderately well off. The very well off ship their offspring off to private schools; but it is their companies that benefit from a well-educated public. (If you don't think that's a benefit, go start up an engineering firm, or even a factory, in El Salvador. Or Watts.)