The richest 50% pay 98% of the taxes.
It's more like 96%. And I suspect that applies only to federal income tax. So it doesn't count payroll taxes. (Social security and Medicare.)
And if the richest 50% own 99% of the wealth, then they are still underpaying.
If you give a tax break it will go obviously benefit the rich the most on a dollar basis even if the less wealthy get a larger % tax cut.
But if the purpose of a tax cut is to stimulate the economy, then it should go to people who will spend it. Otherwise, it's no stimulus. And the people who will spend it are the poor and middle class, not the wealthy. That's why many economists suggested that payroll taxes should be cut, not income taxes. That would help working folk, and businesses as well, since the employers and employees each pay half.
Is that fair? Maybe not. But we've always had a progressive tax system. That is, taxes are based on your ability to pay. If we're going to throw that by the wayside, fine, but then we should also get rid of deductions for dependents. Why should a single person pay more than a family? Families use government services more, they should pay more. "Fair" would be a poll tax. You pay a fixed amount for each person in the household.
And speaking of businesses...in the 1950s, corporate income taxes accounted for something like a third of all revenue. Now, corporate taxes are only 7%. I remember one year, people were outraged because General Electric's state tax bill in NY was $275. GE is a huge company, with several large plants in the state. The toxic waste they've spewed from various sites have polluted the Hudson River, where New Yorkers' drinking water comes from, and many other places. But they paid less in taxes than many individuals.
Our tax system was set up in the 1930s. It is no longer adequate for our global economy. Companies make use of the taxpayer provided amenities, like roads and bridges and water and education, but they incorporate overseas and duck U.S. taxes. The tax burden has increasingly shifted from the wealthy to the poor, and from the corporations to individuals.
If you want to know more, check out this book:
http://makeashorterlink.com/?C19321A09
It's called
Perfectly Legal: The Covert Campaign to Rig Our Tax System to Benefit the Super Rich - and Cheat Everybody Else, by David Cay Johnston.
Think he's a bleeding-heart liberal? Wrong. He's a tax expert, and a registered Republican.