each representative should represent approxi-
mately an equal number of people.
The Constitution directs that the representa-
tives shall be apportioned among the several states
“according to their respective Numbers,” that is,
proportionally. It does not state, however, how
this proportionality is to be achieved. Over the
past two centuries, Congress has used at least four
different methods to apportion the seats among
the states, and several others have been proposed.
Each of the apportionment formulas has produced
quite different results. Currently the Hill method,
also known as the Hill-Huntington method, is
used. It was proposed by University of Harvard
mathematics professor Edward V. Huntington and
statistician Joseph A. Hill.
During the fi rst decades of the 20th century,
migrations brought about huge inequalities in dis-
tricts’ populations. Congress, however—and many
states—refused to redraw district boundaries.
Voters in underrepresented districts often sought
relief in courts as their voting strength was weaker
than that of the voters in other districts. In C
OLE-
GROVE V. GREEN, 328 U.S. 549 (1946), the Supreme
Court held that redistricting cases were not within
the Court’s jurisdiction.
By the 1960s, differences among districts’
populations swelled to larger than 1:100, but the
courts followed Colegrove in holding that redis-
tricting matters are nonjusticiable, meaning that
the courts could not hear them. But in Gomilion
v. Lightfood, 364 U.S. 339 (1960), the Supreme
Court admitted for the fi rst time that the redis-
tricting plan could be a tool for discrimination
on the basis of race. BAKER V. CARR, 369 U.S. 186
(1962), and Gray v. Sanders, 372 U.S. 368 (1963),
finally overruled Colegrove and developed the
“one person, one vote” rule.
The principle of “one person, one vote” was
followed in a series of Supreme Court cases. In
these cases the principle was extended to all levels
of government and was further defi ned. In Wes-
berry v. Sanders, 376 U.S. 1 (1964), the Court
struck down the election of members of Congress
from unequally populated districts. In REYNOLDS
V. SIMS, 377 U.S. 533 (1964), the Court applied
the equal protection clause to invalidate
unequally weighted voting in state legislative elec-
tions; and in A
VERY V. MIDLAND COUNTY, 390 U.S.
474 (1968), the principle of “one person, one vote”
was extended to local elections.
Following these decisions, the Court defi ned
different standards for congressional districts on
the one hand and state and local election districts
on the other. In state and local districting plans,
population disparities under 10 percent generally
require no justifi cation from the state, and even an
89 percent deviation has been upheld for preserv-
ing county borders (see Guffney v. Cummings,
412 U.S. 772 [1973], and Brown v. Thompson,
462 U.S. 835 [1983]). On the other hand, among
congressional districts within a particular state,
exact mathematical equality is required. This was
confi rmed in Karcher v. Daggett, 462 U.S. 725
(1983), when a deviation of less than 1 percent
from population equality was not sustained due to
the lack of a proof of a good-faith effort to achieve
mathematically exact apportionment. In 2002,
even a population discrepancy of as little as 19
people has been struck down following Supreme
Court precedent (Vieth v. Pennsylvania, 195 F.
Supp. 2d 672 [M.D. Pa. Apr 08, 2002], appeal dis-
missed by Jubelirer v. Vieth, 537 U.S. 801 [2002],
and appeal dismissed by Schweiker v. Vieth, 537
U.S. 801 [2002]).
Some authors see this insistence on precise
equality of district population as curious in light
of the fact that distribution of 435 seats among the
50 states inevitably entails more than 70 percent
deviations among districts of different states (see,
for example, Baker, Gordon E., “Whatever Hap-
pened to the Reapportionment Revolution in the
U.S.,” in Grofman, Bernard, and Arend Lijphart,
Electoral Laws and Their Political Consequences
[New York: Agathon Press, 1986], 275–276).
The districts can be drawn in such a way that
boundaries are manipulated for an unfair elec-
toral advantage by a certain party, candidate, or
racial, ethnic, or other group. Such manipulation
is termed gerrymandering. Based on the type of
group that is being advantaged or disadvantaged by
the manipulation, one distinguishes between par-
tisan, racial, or ethnic gerrymandering. In order
to prevent gerrymandering, a number of rules
redistricting and reapportionment 595
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