Boehner's and the GOP's stance that revenue must come from closing loopholes and limiting deductions is bad for certainty
On the one hand, you could tell people hitting that $250,001 income level that the only new tax they're going to pay is a slightly higher rate on income at and above that level. On the other, you tell them that their rate will remain in limbo, but they will be hit, at some point, by the elimination of loopholes. Which loopholes? We'll find out later!