It's obviously true that earmarks are not a significant cause of rising federal spending; eliminating all of them will save at most one percent of the budget. I've always suspected that this is the main reason why right wingers focus on them so obsessively--it makes them look tough on spending while actually doing nothing meaningful to cut it.
That said, I think earmarks are underrated in terms of their contribution to corruption. It's really poisonous when members of Congress can so easily direct federal spending to a favored business in order to attract campaign contributions or just the mistaken belief that they are doing something for their district by helping out a local company.
Furthermore, I think the idea that if Congress stops earmarking that they will somehow disappear is ludicrous. It will just increase congressional pressure on the administration to include favored projects in the president's budget, which for some reason is always treated as being earmark-free.
