
The problem is that the use of earmarks isn't always a bad thing. They are easy whipping boys, but in fact they are actually an efficient way for Congress to provide more specific direction on the expenditure of funds it appropriates. In theory (and sometimes in practice), earmarks remove bureaucratic discretion and increase democratic responsiveness. They are also important instruments of legislative compromise.
The popular disgust with rewarding legislators with earmarks in exchange for votes is understandable but overwrought. The general public does not have a sufficient understanding of the legislative process or the likely consequences of removing opportunities to bargain for votes.
Not much legislation that passes through Congress benefits -clearly & directly- enough states/congressional districts to gain passage. Many laws now beloved by overwhelming majorities of Americans would not have been passed without the ability of leaders to use things like earmarks to sweeten the pot for members for whom a vote would be difficult.
The Framers of the Constitution may not have wanted the legislative process to work smoothly, but neither did they want it to grind to a halt. While the importance of "earmarks" to legislative compromise is not absolutely clear, neither is the notion that they are merely tools of corruption.