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Congress: A Political-Economic History of Roll-Call Voting
EH.NET BOOK REVIEW
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
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