Senate Minority Leader Mitch McConnell is correct that earmarks are a tiny portion of the federal budget, and that even if Republicans stopped earmarking, the bottom line on spending bills might not change.

But Sen. Jim DeMint is also correct that earmarks are a gateway drug to political corruption, or at least compromising one’s principles. In other words, the reason to oppose earmarks — or at least call for serious reform of them — is to clean up the culture of Congress.