On the separation of executive and legislative powers: Executive independence, liberty, and social welfare
| Date | 01 October 2021 |
| Published date | 01 October 2021 |
| Author | Justin Fox,Mattias Polborn |
| DOI | 10.1177/09516298211043234 |
| Subject Matter | Original Research Articles |
On the separation of executive
and legislative powers:
Executive independence,
liberty, and social welfare
Justin Fox
Department of Political Science, Washington University in St. Louis,
St. Louis, MO, USA
Mattias Polborn
Department of Economics and Department of Political Science,
Vanderbilt University, Nashville, TN, USA
Abstract
We explore the effects of a particular facet of separation of powers—namely, the executive’s inde-
pendence from the legislature—on maintaining a norm of legislative restraint in which antagonistic
factions refrain from passing laws that infringe on their rival’s liberties. Our main result establishes
that executive independence may sometimes undermine and at other times facilitate legislative
restraint, depending on the probabilities with which the factions hold legislative and executive
power. Our results contribute to the larger game-theoretic literature exploring the effects of poli-
tical institutions; our results also contribute to the literature exploring how institutions designed
to protect liberty affect tacit cooperation among rival factions.
Keywords
Separation of powers, enforcement, tacit cooperation
In all tyrannical government, the supreme magistracy, or the right of both making and of enfor-
cing the laws, is vested in one and the same man, or one and the same body of men; and wher-
ever these two powers are united together, there can be no public liberty.—Sir William
Blackstone (Blackstone 1893: 144).
Corresponding author:
Justin Fox, Department of Political Science, Washington University in St. Louis, St. Louis, MO 63130, USA.
Email: justin.fox@wustl.edu
Original Research Article
Journal of Theoretical Politics
2021, Vol. 33(4) 430–454
© The Author(s) 2021
Article reuse guidelines:
sagepub.com/journals-permissions
DOI: 10.1177/09516298211043234
journals.sagepub.com/home/jtp
1. Introduction
How does executive independence from the legislature affect liberty? While various
explanations have been offered for how separating executive and legislative powers
can preserve liberty (Waldron 2013), the most straightforward is that when one body
is endowed with legislative power and another body is endowed with executive power,
then two separate wills must act in concert for liberty to be infringed upon, whereas
when powers are unified in one body, only one will is required for liberty to be infringed
upon.
We do not challenge this presumption, but explore instead how separating executive
and legislative powers affects a norm of legislative restraint. Under such a norm, rival
factions refrain from passing liberty-infringing legislation while in power to avoid
being retaliated against when out of power. In what follows, we set up an infinite-horizon
model of lawmaking and enforcement, and analyze the effect of a particular form of
executive independence—namely, the ability of the executive to underenforce
legislation—on the willingness of the factions to cooperate.
1
The key insight generated by our model is the following: The ability to underenforce
legislation generates two distinct forces, and these forces may hamper or facilitate legis-
lative restraint depending on their respective size. To see this, suppose that the current
legislative majority has the executive’s support in infringing on the other group’s
liberty, but such infringement results in a breakdown of future legislative restraint. The
ability to underenforce legislation insures, to some extent, against future retaliation by
the other group,
2
which makes infringing on the other group today more appealing.
On the other hand, the possibility of underenforcement limits the ability of the current
legislative majority to oppress the opposing faction whenever (at some future point)
the latter controls the executive. This second effect makes infringing on the other
group today less appealing, and therefore enhances the prospects for legislative restraint.
Which effect dominates, as we shall show, depends upon each faction’s electoral strength
at the legislative and executive level.
Turning to the details of our theoretical framework, ourinfinite-horizon model is set in a
world with two antagonistic political factions (or, synonymously, parties), and two institu-
tions, a legislature and an executive. In each period, the faction that currently controls the
legislature must decide whether to pass a law that infringes on the liberty of the other
faction. Such infringement benefits the group in power at the expense of the other
group. Moreover, when the cost of being infringed upon is sufficiently large, there is the
potential for a tacit, mutually-beneficial non-aggression pact (a norm of legislative
restraint) whereeach faction foregoes infringement as long as the otherside does the same.
We assume that the executive decides the degree to which an infringing law, if passed
by the legislature, is enforced. Less enforcement proportionately lowers the benefits and
the costs from the law. The enforcement choice is constrained by what we call the degree
of executive independence—a completely independent executive can essentially nullify a
liberty-infringing law by not enforcing it (and will do so if he belongs to the targeted
faction), while an executive without independence has no choice but to faithfully
enforce whatever laws are on the book.
3
We examine how the degree of executive inde-
pendence affects whether a norm of legislative restraint can prevail.
Fox and Polborn 431
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