much as in the current period. For example, this paper focuses on the 1850s period, when slavery was
central to ideological thinking, but not to partisan action.
Politics in the 1850s was also about party and ideology, but they were easy to distinguish. The
issues that divided the parties reflected a commercial vs. agricultural conflict, but not slavery. Slavery and
the “Slave Power” were a source of controversy, but they were not controversial between the parties. To
be a Whig or a Democrat said nothing about being pro- or anti-slavery. That is, slavery was as an
orthogonal issue that cross-cut the existing party system. But I find that when we measure ideology
independent of Congress, as I do in this paper, the picture is different. Slavery was not an orthogonal
issue; it was well-integrated into an ideological dimension that included trade and the other partisan issues
of the day. Mercantilists who wanted government aid in building a national economy opposed slavery,
and those opposed to pro-business protections like the tariff favored slavery. My data include some
thinkers who took other positions, but this is the dominant division among political intellectuals. It is thus
too simple to say that the issue of slavery broke apart the party system. Rather, an ideological system that
incorporated slavery was incompatible with a party system that did not. I argue that had ideology not
incorporated slavery, the realignment of the 1850s might not have occurred. The organization of the issue
into a block of committed believers forced a change in the party system.
This finding is at variance with the accepted political science account of the formation of parties
(Schwartz 1989, Aldrich 1995), in which elected legislators form logrolls in Congress that are cemented
as parties. The Democrats and the Whigs were attempting to hold together logrolls in the legislature, but
they did not attempt to organize the issue of slavery. But actors outside the legislature did take up slavery,
making it part of the dominant ideological division of the day. At that point elected officials had to
respond to a world where slavery was not only on the agenda, but was part of the prevailing ideological
division. Congressmen had to get themselves nominated and elected by activists holding ideologies in
which slavery was a central element. Eventually, the unwillingness of Whigs to bend to the will of anti-
slavery, protectionist ideological activists meant the party would give way to a Republican Party that did
heed them.
2
Convention