Published by EH.NET (August 1998)

Keith Poole and Howard Rosenthal, Congress: A Political-Economic History of

Roll-Call Voting. New York: Oxford University Press, 1997. x + 297 pp.

$85.00 (cloth), ISBN: 0-19-505577-2

Reviewed for EH.NET by Jac

Heckelman, Department of Economics, Wake Forest University.

Over the last decade and a half, Keith Poole and Howard Rosenthal have

published several papers analyzing congressional roll-call voting behavior.

In this new book, they pull together and extend this work, presenting their

methodology and findings, and covering every Congressional roll-call vote from

1789 to 1985. The authors express their desire to make their research useful

to economic historians. Fortunately, they have largely succeeded.

The main purpose of the book is to detail how roll-call voting is useful for

determining legislators’ ideological positioning in a spatial model.

Their main conclusions are that (1) ideology outperforms “economic” models of

voting; (2) ideology is low dimensional; (3) ideological positions remain

fixed throughout a legislator’s tenure; and (4) mass political realignments

among the voters are not matched by changes in roll-call voting except from the

new legislators.

After a brief introductory chapter that nicely outlines the structure and

highlights of the book, they present the basic methodology in chapter 2.

The spatial voting model they develop assumes that legislators will vote for or

against an issue based on which side of the roll-call midpoint they are on, as

expected by the Median Voter Theorem. Rather than rely on strict deterministic

voting, the model instead is based on probabilistic voting where those closer

to the option are more likely to vote for the option.

Their model is supported by the finding that errors on predicted voting are

primarily for those legislators close to the “cutting point” which identifies

the location of the split between supporters and opponents.

Although explicit details of the exact methodology may not be of particular

interest to historians, it should be stressed that the only variable used is

the actual roll-call votes. Poole and Rosenthal are correct to point out that

their methodology is not very useful for predicting voting outcomes,

rather it is designed for identifying the positions of each legislator and the

cut point along the spatial dimension.

The next chapter presents evidence that ideology can readily be captured in

only a single dimension and thus the simplest model can be estimated. A second

dimension is only required in a few instances (discussed below) when racial

issues are specifically involved. For those not interested in this finding, the

chapter can be skipped without impeding the rest of the book.

Chapter 4 is dedicated to the issue of party polarization. In this chapter the

authors present a lot of stylized evidence, which makes for interesting

reading. They conclude that Congress has been most polarized in the

post-Reconstruction through WWI period, and least polarized in the post-WWII

period, due to the North/South split in the Democratic Party.

Poole and Rosenthal suggest the second dimension of race came into play due to

civil rights issues in New Deal legislation which pushed the Southern Democrats

further right in their ideological leanings. This interpretation is

questionable since their analysis shows the first dimension movement actually

began at the turn of the century and thus New Deal movement may only be the

continuation of a prior trend. They also show that regional differences are not

limited to the twentieth century. For example, Northern Whigs were consistently

further right than Southern Whigs from 1827 to 1847, and the Whigs were further

right than Democrats. But on slavery issues, the second dimension shows the

southerners of both parties were more conservative than the northerners.

Although most of the evidence is presented graphically throughout the book,

this chapter is slightly marred by the inclusion of some ad hoc regressions

which do not add much to the analysis.

The chapter on realignment is likely to be the most controversial among

political historians. Political scientists typically refer to realignment as a

change in voting behavior among the mass electorate, whereas Poole and

Rosenthal define realignment as a change in roll-call voting. Their rationale

for this new definition is as follows: “If an issue is to result in sustained

public policies, we hypothesize that the policies must eventually be supported

by a coalition that can be represented as a split on the first, or major

dimension. Policy developed by coalitions that are non-spatial or built along

the second dimension is likely to be transient and unstable” (p. 112). Under

their definition, Poole and Rosenthal find that a legislative realignment

occurred only once in U.S. history, this being in 1851-2 due to the extension

of slavery to territories. This chapter is particularly strong on detailing the

sequence of voting on slavery issues by party and region. Contrary to

conventional wisdom, their analysis shows the realignment occurred before the

Republicans became a strong political force in Congress. The findings of

non-realignments are especially intriguing. Among many historians, the

realignment of 1896 is considered a political fact. Poole and Rosenthal claim

this to be a “false realignment” since only the importance of inflation

changed, but not voting patterns on monetary issues. A regional East-West split

remained but is captured in the first dimension and thus the model stays stable

throughout this period. Similarly, the authors show the supposed “New Deal

realignment” was simply a massive change in party composition in Congress,

and thus a differing voting agenda occurred, but again roll-call behavior

remained markedly stable among individual legislators. While I am certainly

sympathetic to their interpretation, I expect traditional political historians

are unlikely to be convinced and may cite this instead as evidence that

Congressional realignment is less important to determining the direction of the

nation than traditional analysis of the mass electorate. Finally, Poole and

Rosenthal uncover a slight “perturbation” in the 1950s as civil rights issues

split the Democratic party, but this is directly captured by including a second

dimension to voting and never dominates the first dimension voting on

traditional economic issues.

After the excitement of turning realignment theory upside-down, things return

to a more mundane level in chapter 6 where it is shown that the senators from a

given state (and party) do not typically vote the same way.

This is given as evidence that legislators vote based on their individual

ideology, and spatial ideology outperforms the purely economic median voter

models. Once ideology is included, there is weak correlation of the residuals

by state. Case studies are presented for food stamp programs in 1964 and 1967,

railroad regulation from 1874 to 1887, legislation on the minimum wage from

1937 to 1990, strip mines in 1974 and OSHA in 1975. These results are well

established in the literature, and their presence here serves only to reiterate

the findings (some of which are their own from earlier studies).

The issue of strategic voting is finally considered in Chapter 7 where we learn

that cases of strategic voting throughout history are extremely rare.

It is unfortunate that this important topic is relegated to its own chapter

toward the end of the book, as the interpretation of ideology would be altered

if legislators engaged in strategic voting. Furthermore, the authors

incorrectly argue that strategic voting should not occur in single dimensional

space, and therefore only consider the cases when race creates a second

dimension. This conclusion is valid only if legislators have single-peaked

preferences in their utility functions. If preferences are not single-peaked,

cycling and strategic voting are still possible even in a single dimension.

Although single-peaked preferences are an explicit assumption of their model,

this was presented at the start of the book and needs to be reiterated here. If

this assumption fails to hold, strategic voting may be more problematic than

they allow for. The chapter includes only brief discussions of strategic voting

in the political science literature, which includes (in order of presentation)

the 1965 School Aid Bill and Powell Amendment, the 1846 Wilmot Proviso, and the

1911 DePew Amendment.

Scholars often measure legislator ideology from various interest-group ratings,

which only consider a subset of votes in any year. Chapter 8 shows a high

degree of correlation between the most commonly utilized ratings and Poole and

Rosenthal’s predicted scores based on all votes. This is an important finding

since interest group ratings are not available prior to the 1960s.

The last two chapters on committee representation and legislator abstention,

are unlikely to be of specific interest to historians as they only present

broad trends and do not include the insightful discussions of individual

historical case studies of the previous chapters.

The flaws discussed above are minor compared to the great strengths of the

book. The book is highly recommended for anyone interested in the history of

roll-call voting and the careful analysis of legislator ideology.

Jac Heckelman Department of Economics Wake Forest University

Jac Heckelman studies issues in historical political economy. He is the author

of “The Effect of the Secret Ballot on Voter Turnout Rates,”

Public Choice 82, 1995; “Political Business Cycles Before the Great

Depression,” (with Robert Whaples) Economics Letters 51, 1996;

“Determining Who Voted in Historical Elections: An Aggregated Logit Approach,”

Social Science Research 26, 1997; “Employment and Gubernatorial

Elections During the Gilded Age,” Economics and Politics