if you make over 250K.
The reason is that the Bush tax cuts will expire in 2010.
There would be nothing a President McCain could do to stop this from happening. He can't change tax rates via executive order, and the Democratic majority doesn't have to worry about a veto...all they have to do is nothing, and rates will go back up to what they were during the Clinton administration.
So voting for McCain because you're against the tax increase for the top bracket is pretty pointless, because that rate is going to go up anyways.
