The structure of Congress 399The Role of Parties and Conditional Party Government Political parties
in Congress also reflect the individualism of the institution. Compared with
parliamentary systems, U.S. congressional parties are very weak. They do not impose a
party line or penalize members who vote against the party. Indeed, they have virtually
no ability to impose electoral restrictions (such as denying the party’s nomination) on
renegade members.
Although still weaker than their overseas counterparts, parties in Congress have
greatly strengthened since the 1960s (see Figure 11.5). Partisanship—evident when
party members stick together in opposition to the other party—reached its highestFIGURE
11.5Party Votes and Unity in Congress, 1962–2017
(A) Party votes are said to occur when a majority of one party opposes a majority of the other party,
and (B) party unity refers to the percentage of the party members who vote together on party votes.
These two graphs make two important points. First, partisanship has increased in the last two decades,
in terms of both the proportion of party votes and the level of party unity. Second, despite these
increased levels of partisanship, only about two-thirds of all votes in the House and Senate divide the
two parties. Given these potentially conflicting observations, how would you assess the argument that
partisanship in Congress is far too intense?Source: CQ Roll Call, http://cqrollcall.com/cq (accessed 10/1/18).0
20
40
60
80
100%
(A) Party votes in Congress1962 1972 1982 1992 2002 2012 2017
HouseSenate2017
0
40
20
60
80
100%
(B) Party unity score1962 1972 1982 1992 2002 2012
House RepublicansSenate DemocratsHouse Democrats
Senate RepublicansFull_12_APT_64431_ch11_374-417.indd 399 16/11/18 10:30 AM