The shift in tax burden from the wealthy to them. While not a monetary increase yet, if the government borrows money, paid for by taxpayer A-Z, to give a tax cut to taxpayer A-F, G-Z pick up the burden. Effectively, its a tax increase, since the government borrowed the money and they’re paying a higher percentage now.
Here’s an old article from a study by a non-partisan, Republican-headed gov. agency.
http://www.washingtonpost.com/wp-dyn/articles/A61178-2004Aug12.html