Multi-Part Tests in the Jus Ad Bellum

30 Pages Posted: 2 Apr 2016 Last revised: 10 Nov 2017

See all articles by Ashley Deeks

Ashley Deeks

University of Virginia School of Law

Date Written: April 29, 2016


As the U.N. Charter’s drafters might have predicted, various categories of cases have arisen since 1945 in which states have sought to use force in situations not expressly contemplated by the treaty text. Those who view the Charter as a “living instrument” urge flexibility in interpretation when approaching these nonstandard cases. But they also recognize that allowing excessive flexibility will destabilize the Charter. As a result, some states and scholars seek to promote constrained flexibility by proposing multi part tests to guide state decision making in these nontraditional cases. The MPTs propound on the meaning of sparse texts by articulating specific, legalistic elements or factors against which states may evaluate their contemplated actions.

This Article identifies the common use of MPTs in the jus ad bellum to structure and assess state uses of force in nontraditional contexts. Analytically, it explores why states and scholars turn to MPTs, arguing that MPTs emerge where treaty amendments or Security Council authorization are unlikely. Although not binding on states that have not adopted them, MPTs promote law specification and development and offer a way to reduce interstate conflict. The Article also argues that an MPT will garner more support when it is more rule like and when it closely tracks the underlying Charter or customary rule on which the MPT expounds. Using that analysis, it predicts that MPTs in the area of humanitarian intervention are likely to encounter continued skepticism, at least in the near term.

Keywords: Jus ad bellum, Use of force, Multi-part tests, Defense of nationals, Cyber, Anticipatory self-defense, Humanitarian intervention, Unwilling or unable

Suggested Citation

Deeks, Ashley, Multi-Part Tests in the Jus Ad Bellum (April 29, 2016). Houston Law Review, Vol. 53, p. 1035, 2016, Virginia Public Law and Legal Theory Research Paper No. 2016-30, Available at SSRN:

Ashley Deeks (Contact Author)

University of Virginia School of Law ( email )

580 Massie Road
Charlottesville, VA 22903
United States

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