Hvg krause 47K. qxd

it cannot be upset, for there is no region where at least 

five of the pre-

ferred-to sets overlap.

We can now develop our six models. There are several variables whose

values collectively de

fine each system. Phrased as questions, these vari-

ables are as follows.

1. Does the system have one institutional veto point (as in uni-

cameralism), two institutional veto points (as in bicameralism),

or three institutional veto points (as in a presidential system

with a bicameral legislature)?

2. Within each institutional veto point, is there one party, two par-

ties, or three parties?

3. Does the governing party or coalition have monopoly agenda

authority (i.e., it alone can present motions on the 

floor) or can

the opposition party or parties propose a motion on the 

floor?

4. Will a governing party or a coalition send a proposal to the 

floor

only if it is sure to be approved on a 

floor vote or will such a pro-

posal be made even if it could be defeated on a 

floor vote?

5. Do any parties in the system exhibit perfect party discipline (i.e.,

each party member always votes for some of

ficial party position

on a 

floor vote) or are party members free to vote for or against

any of

ficial position their party adopts?

6. Do the members of any opposition party automatically vote

against a proposal by some governing party or coalition or do the

members of the opposition consider voting for such a proposal?

Our six models represent just some of the many possible combinations.

Nonetheless, these models demonstrate that the size of a system’s set of

equilibrium policies, and thus the extent of its bureaucratic autonomy,

are very sensitive to the details of these procedures and practices.

A Two-Party Unicameral Parliament with 

Perfect Majority Party Discipline

Our 

first model involves a unicameral parliament in which the majority

party has perfect party discipline. In particular, we assume that the ma-

jority party adopts its most preferred policy via majority rule within the

party and once this party position is adopted all party members will sup-

port it in a vote against SQ. We further assume that the majority party

has monopoly control over the legislative agenda (i.e., the minority party

Veto Points in Democratic Systems

81

---

Politics, Policy, and Organizations

cannot propose its own motion). Next, we assume that minority party

members automatically vote against the majority party motion; the ma-

jority party cannot count on help from minority party members to pass

its bills. Finally, we assume that the majority party will propose a motion

to the 

floor only if that motion will defeat the status quo policy.

To illustrate, assume there are nine members of parliament who are

partitioned into the Labor and Conservative parties. As indicated in

figure 2A, we assume that the Conservative Party has five members, C

1

through C

5

, and that the Labor Party has four members, L

1

through L

4

.

As the majority, the Conservative Party’s most-preferred policy position

lies at its party median at C

3

. Because the Conservative Party has a ma-

jority and because of its party discipline, any SQ will be replaced by the

of

ficial party policy at C

3

. Because this policy at C

3

cannot be upset, it is

the Majority Party Unicameral Core.

If an election is held and Conservative Party member C

1

is replaced

with Labor Party member L

5

(and everyone else remains the same), then

the Labor Party has the majority. The ideal point of its median member,

L

3

, would then become its most-preferred policy position, which would

thus become the Core (see 

fig. 2B).

If the majority party has an odd number of members, as in 

figures 2A

and 2B, then the Majority Party Unicameral Core will be the single pol-

icy at the ideal point of the median party member. If the majority party

has an even number of members, then the size of the Core depends on

how far apart are the ideal points of the party’s median members. For ex-

ample, if the two median members of a six-member Conservative Party

have identical ideal points, as in 

figure 2C, then the Core will include

just their common ideal point. If their ideal points are far apart (e.g.,

when the party is divided into two distinct factions), the Core would be

rather large, spanning the set of policies between the median members’

ideal points. In 

figure 2D, for example, the Conservative Party has two

distinct three-member factions; hence, the Core spans the region be-

tween the two median party members, C

3

and C

4

.

A Two-Party Unicameral Parliament without Perfect Majority

Party Discipline

Assume now that the majority party’s discipline is not perfect: any mem-

ber may vote against any proposal of his or her own party if the member

prefers the status quo. Assume that minority party members continue to

82

---

Fig. 2. A two-party unicameral parliament with perfect majority party discipline

---