Logrolling refers to the exchange of political support, particularly in the legislative process. The term arose, with disreputable connotations, within the discourse of (extremely) practical American politics. In recent decades the term has entered the vocabulary of academic political science, and some political theorists have argued that logrolling can promote the efficient and equitable satisfaction of political interests and values.
The term 'logrolling' evidently arose on the early American frontier. When trees were cut to clear land for farming and to build log houses, heavy logs had to be rolled out of clearings and to building sites -- a task beyond the strength of a single person or family. Hence reciprocity arose among neighbors: 'I'll help roll your logs if you'll help roll mine.' By 1809, the term was applied by commentators and editorialists to characterize -- but also to condemn as immoral -- assorted instances of political trading in the early American republic. (See the entries in Safire, 1993, and Sperber and Trittschuh, 1962.)
The negative connotations associated with logrolling might seem puzzling. After all, the frontier practice after which it is named was surely constructive and praiseworthy. And logrolling may appear to be analogous to voluntary economic exchange, the desirability of which is supported by a massive edifice of theory and evidence. Indeed, the earliest use of the term in academic social science did not condemn it. While conceding that it is 'a term of opprobrium,' Arthur Bentley asserted that 'log-rolling, or give and take, appears as the very nature of the [legislative] process. It is compromise . . . in the practical form with which every legislator who gets results through government is acquainted. It is trading. It is the adjustment of interests.' (1908, pp. 370-378.)
By the late 1950s and early 1960s, some economists (notably James Buchanan and Gordon Tullock, 1962) and political scientists drew an explicit analogy between economic and political exchange, from which they often drew positive normative implications as well. Since then, the phenomenon of logrolling has received considerable attention in political science and political theory. Focus on the welfare implications of logrolling has raised a number of analytical problems. These include: the prevalence of logrolling as a function of the nature of decision rules, electoral systems, and party systems; the extent to which logrolling takes account of preference 'intensities'; whether logrolling avoids or generates the 'cyclical majority' problem; and whether logrolling produces stable and predictable outcomes.
Let us consider some of these issues by means of stylized examples. First, we have the case of ordinary economic exchange. Suppose A grows nothing but apples and B nothing but oranges, so A controls the allocation of apples between them and B the allocation of oranges. Since each actor prefers more fruit to less, neither would unilaterally transfer fruit to the other. But if A and B each prefers a mixed diet, they can both benefit by trading fruit. We may note three points. First, the fact of mutually beneficial trade depends on 'finer' aspects of the actors' preferences (their 'marginal rates of substitution') that are otherwise irrelevant. Second, since the trade is in private goods, no one else is affected and mutually advantageous trade unambiguously increases social welfare. Third, if (say) apples come in season before oranges, B would have to be able to make a credible promise (e.g., by means of an enforceable contract) to A for the gains from trade to be realized.
Second, let us consider political exchange in a non-legislative (e.g., bureaucratic) context. Suppose that A and B are political actors who unilaterally control 'issues' X and Y respectively. Each issue can be resolved in one of two ways: x1, x2 and y1, y2 respectively. A prefers x1 to x2 and y2 to y1, while B has the opposite preference on each issue. Thus if A and B act unilaterally, the outcome is (x1, y1). But if both prefer (x2, y2) to (x1, y1), they can benefit from a 'logrolling agreement' such that each trades his preference on the issue he controls (but cares less about) for his preference on the issue he doesn't control (but cares more about).
We can draw the following conclusions. First, while logrolling (like economic exchange) depends on finer preference information, it does not depend on interpersonal comparison of preference 'intensities.' Second, a logrolling agreement is unambiguously welfare increasing if no other actors are affected by issues X and Y or if A and B are perfect representative agents of the affected groups. But this proviso is unlikely to be realized in a political context, so the welfare implications are uncertain. Third, non-legislative logrolling agreements cannot be upset by other actors.
Next, let us suppose that A and B are legislators, each endowed with a single vote on each of two legislative issues X and Y, on which their preferences are the same as those specified above. 'Pork-barrel' (or 'distributive') politics, which arises when the central government finances the construction of public works projects whose benefits are received locally, may give rise to such preferences, especially if legislators are elected from small districts that approximate the catchment area for benefits.
Suppose further that A and B are each in the minority with respect to the issue they care more about (e.g., their own projects), but that the support of the other legislator would convert each minority into a majority. Then A and B can engage in a logroll (or 'vote trade'), each agreeing to vote contrary to his preference on the issue he cares less about, thereby switching the legislative outcome from (x1, y1) to (x2, y2) in the manner they both prefer.
But in legislative context, the actors are trading only votes on issues-- not unilateral control -- so the preferences and actions of other legislators are relevant. Even if A and B are perfect representative agents of their constituents, the (potential) switch from (x1, y1) to (x2, y2) clearly affects other legislators and their constituents, and other legislators with opposite preferences between (x1, y1) and (x2, y2) may be in position to "counter-logroll," neutralizing the potential effect of the vote trade between A and B.
However, if the coalition of A and B constitutes a majority of the legislature (i.e., if the body has only three members or if A and B are sufficiently large blocs with identical relevant preferences), their logrolling agreement cannot be upset by the residual minority. The term 'logrolling' is often reserved to describe the formation of such a majority-sized 'coalition of minorities' (of course, a coalition encompassing many issues may be needed), while 'vote trading' is applied to the kind of pairwise trading described above.
While such majoritarian logrolling cannot be upset by the minority outside the supporting coalition, excluded legislators can try to break apart the logrolling coalition by offering proposals to knock out one or a few projects. Any such proposal advantages everyone except the few beneficiaries, which implies that logrolling agreements are intrinsically unstable. (This also implies that logrolling is feasible only in the presence of 'cyclical majority' preference over the possible outcomes -- a point discovered independently and more or simultaneously by many different researchers in the early 1970s; see Miller, 1977, for a general review.)
It is generally believed that this kind of 'explicit' logrolling is especially prevalent and visible in the U.S. Congress -- prevalent because of its single-member district system and because a 'checks and balances' structure requires broad-based coalitions and visible because weak party discipline allows members to cut their own deals. But 'implicit' logrolling engineered by political entrepreneurs attempting to assemble winning coalitions is undoubtedly even more widespread, occurring in the construction of legislative programs and party platforms or manifestos, within one-party cabinets, and in inter-party negotiations leading to coalition governments.
Finally, let us reconsider the welfare implications of legislative logrolling, using the example of pork-barrel politics. We have two possibilities: (i) the proposed projects are (on average) efficient, i.e., their benefits exceed their costs; or (ii) they are (on average) inefficient, i.e., their costs exceed their benefits. The virtue of logrolling is that even efficient projects cannot command anything like majority support as stand-alone proposals, so logrolling (of some type) is necessary to assemble the support needed to authorize them. The defect of logrolling is that even somewhat inefficient projects can be packaged together to secure majority support. Indeed, if a logrolling coalition is built up sequentially, something like an n-person Prisoner's Dilemma may result: at every stage, each legislator has a strong incentive to see his own project included in the logrolling agreement but, as more other projects are included as well, the net advantage to each member of the expanding logrolling coalition diminishes and may become negative, with the result the everyone would be better off if the logrolling process had never started. (This is essentially the story told by E. E. Schattschneider, 1935, concerning the Smoot-Hawley Tariff passed by the U.S. Congress in 1930, and this scenario is explored formally by Riker and Brams, 1973.) Thus we cannot make a conclusive normative judgment concerning logrolling. But the widespread condemnation of the practice appears to be based on largely unexamined presuppositions rather than analysis. Most students of politics are probably inclined to endorse Bentley's assessment and to be skeptical of proposals (e.g., to use new technologies to set up a referendum democracy) that would wholly preclude logrolling.
Bentley, Arthur (1908) The Process of Government, Chicago: University of Chicago Press
Buchanan, J. M., and Tullock, G. (1962) The Calculus of Consent The Logical Foundations of Constitutional Democracy, Ann Arbor: University Of Michigan Press
Miller, N. R. (1977) 'Logrolling, Vote Trading, and the Paradox of Voting: A Game-Theoretical Overview', Public Choice, 30: 52-75
Riker, W. H., and Brams, S. J. (1973) 'The Paradox of Vote Trading', American Political Science Review, 62, 4: 1235-47
Safire, W. (1993) Safire's New Political Dictionary, New York: Random House
Schattschneider, E. E. (1935 ) Politics, Pressures and the Tariff, Englewood Cliffs, NJ: Prentice-Hall
Sperber, H., and Trittschuh, T. (1962) American Political Terms: An Historical Dictionary, Detroit: Wayne State University Press