A snippet of a thought: When some of us contribute by paying taxes -- be it into the Social Security system or the federal income tax, or state income tax, or state sales tax -- and others by contributing to our favorite charities, are these equally beneficial to the common good? (We don't give federal income tax deductions for one's contributions to Social Security, which constitute the majority of taxes for most of us. Well, maybe we do, sort of: the standard deduction could be construed as a sort of deduction for SS taxes. I've not played with the numbers.)
When some of us contribute by spending 2 years evangelizing overseas for our chosen religion, and others contribute by spending some years of our lives in military service, at risk to their lives and future well-being, are these equally beneficial to the common good?
And a semi-related thought: it seems likely that the richer candidate's contributions to his chosen charities were in the form of (awesomely) appreciated securities for which his basis was quite low. I've not heard much mention of that. He might have paid income taxes on $1 of "value" when he received it, and gotten a tax deduction on $10 or $100 -- or more -- when he donated it a few years later.
I don't mean this as a partisan thing; I'm not enthralled with either of our current major parties or their candidates, and regard one only as the lesser of two evils. (I think I would find one candidate's Supreme Court appointees more palatable than those of the other, and regard that as the key issue in the federal election.) I'll be voting for various 3rd party candidates for many of the positions on my ballot.
We'd be better off if we tapped into natural public revenue sources -- the rental value of land, the rental value of "location, location, location!", taxes on finite natural resources, such things as the supposedly "public" airwaves, geosynchronous orbits, airport landing rights, water rights -- the value of which today flows into the private pockets of various privileged folks, enriching them without requiring a return of service to the rest of society for that value.