If you're earning under $50K, that's probably what you're already paying.

This works great if the only thing anyone wants from their government is public defense. Want schools, social security, roads safe to travel on? Not going to do it. Want Medicare and Medicaid and any kind of social safety net? Nowhere near.
Most developed countries pay closer to 50% of their income in taxes.

The big issue in "fair share" is that, as Warren Buffet has stated, he shouldn't pay a lower tax rate than his secretary does. Closing the loopholes so that the superwealthy pay the say percent as ordinary working Americans (not more, just the same)would go a ways towards balancing the budget. Far enough? Well, probably not.

1) Actually, I DON'T want the federal gov't involved in education. Definitely should be a state issue.
2) Warren Buffett is a crony capitalist who will always find a way around paying his taxes. This is all showmanship for him while he sucks up to the current administration. Anyway, he doesn't pay a lower tax rate than his secretary does. That is actually not true.
3) 47% of Americans pay NO federal taxes. If the top 0.2% of earners pay 20% of taxes and that's not yet fair, then I say it's not fair the bottom 47% pay nothing. I would like to see them "pay their fair share."

Think about where that 10% tithe came from. It was imposed when the Persian Empire ruled Judea (as its province of Yehud). The temple was the local government, and collected taxes. Half stayed in Yehud and half went to the emperor in Persipolis.

What the Jewish people got for their tithe was protection by the Persian army against invasion by Egyptian or Greek forces, and nominal freedom to travel throughout the Persian empire. That was it. The roads weren't very good, where there were roads at all. Social services were nonexistent, other than any charity the temple might provide. But of course the only people who got temple charity were those who were in favor with the temple, and that meant they were donating far more than the legally required 10%.