The idea is rapidly spreading that a ban on earmarks doesn't affect spending, since earmarks are a way of distributing what's already been appropriated.
This is just true enough to be clever, and marks the speaker as being more sophisticated than those Tea Party rubes. But it's basically false, for three reasons.
First, it is more expensive to do things inefficiently than to do things efficiently. Building the Ted Stevens Bridge To Nowhere or the Robert Byrd Gold-Plated NORAD Auxiliary High Command Of West Virginia means that money has simply been wasted, and that all the needs that weren't met this year will arise again next year. If the real needs exert at least some pull on appropriations levels, then wasting money rather than spending it wisely at time 1 does affect appropriations at time 2. The U.S. gets very bad value per dollar of federal infrastructure spending, in part because earmarks screw up the ability to prioritize projects. That doesn't increase the appropriations at time 1; but it does tend to drive them up in every later year. Similarly, when earmarks keep alive weapons systems that the Pentagon wants to cancel, because the defense appropriators in Congress view the defense budget as a jobs program, the Pentagon shrugs its shoulders and increase its request the following year; it's not going to let the wasteful jobs-program part of the budget displace its own military priorities.
Second, bills often emerge out of House-Senate committees with higher appropriations levels that have the express aim of smoothing passage with earmarks.
But third, and most important: the earmarking members of Congress are the same people who set the appropriations level. And by this I don't only mean that they're members of the House and Senate; I mean that they're powerful members of the relevant committees. Ted Stevens and Robert Byrd took turns chairing the Senate Appropriations Committee. The knowledge that they were going to have a chance to start shoveling pork a little bit later in the process affected how much they appropriated at the beginning.
The idea that earmarks don't affect spending levels rests on a crazy image of how appropriations levels are set. We don't have one set of legislators who are dispassionate, disinterested judges of how much money needs to be allocated, who are then later on replaced by a bunch of grubby politicos deciding how to divvy up the spoils. Neither do we have legislators who, during their initial appropriations deliberations, somehow forget that earmarking comes later. Instead, we have normal human legislators throughout, responding to their incentives and environment. It would take a kind of saintly self-denial for them not to increase the initial size of the pool knowing that they were going to get a chance to give themselves a share later on.
Republican earmark supporters have been saying that abolishing earmarks transfers allocation authority to the dreaded Obama Administration. Well, yes. And if you tell a bunch of Republican legislators to decide how much money to give to the Obama administration to allocate, they'll come up with a smaller number than if you tell them to come up with an amount for them to divide up among themselves to allocate. Indeed the same holds true for members of the President's own party.
Earmarks aren't themselves a lot of money in the grand scheme of things, and abolishing them entirely would only make a tiny dent in the deficit. But they do indeed affect appropriations-- and my hunch is that they affect appropriations for more than their actual cash value, because they create a system that attracts appropriators like Byrd and Stevens, who err on the side of spending too much to make sure there's enough to go around.