Disclaimer. Don't rely on these old notes in lieu of reading the literature, but they can jog your memory. As a grad student long ago, my peers and I collaborated to write and exchange summaries of political science research. I posted them to a wiki-style website. "Wikisum" is now dead but archived here. I cannot vouch for these notes' accuracy, nor can I even say who wrote them. If you have more recent summaries to add to this collection, send them my way I guess. Sorry for the ads; they cover the costs of keeping this online.
Dixit and Londregan. 1996. The determinants of success of special interests in redistributive politics. JOP 58: 1132-55.
Why do some groups get more pork than others? More precisely, why determines whether politicians will funnel pork towards loyalists versus towards swing groups?
X: Parties might be equally able to provide pork to any group, or they may have advantages in providing to only certain groups (i.e. to loyalists).
Y: Will parties compete to provide pork to the same (moderate) groups or provide pork primarily to loyalists?
When parties have an equal ability to provide pork to any group (X), they will funnel pork toward swing groups (Y). Note that parties do not distribute directly to voters that promise to support them; instead, they target pork at groups that have lots of persuadable voters. And a group of voters might be more persuadable for a few reasons:
When parties have a comparative advantage at providing pork to certain groups (e.g. when you have machine politics), then they will channel redistribution toward core supporters. This is more efficient (due to your comparative advantage) than trying to figure out which other groups you might be able to persuade.
Contrast with Stokes (2005).
Research on similar subjects