The International Legality of US Military Cross-Border Operations from Afghanistan into Pakistan

• Author: Sean D. Murphy
• Position: Research Professor of Law, George Washington University Law School
• Pages: 109-139

V

The International Legality of US Military

Cross-Border Operations

from Afghanistan into Pakistan

Sean D. Murphy*

Introduction

Anaspect ofUS military involvement in Afghanistan since 2001 has been the

use of cross-border US operations from Afghanistan into Pakistan, under-

taken for the purposes of striking at the camps, compounds, and convoys of Al

Qaeda and Taliban elements based in Pakistan, and of defending against cross-

border attacks and infiltration by those militants from Pakistan into Afghanistan.

As amatter ofscale, US cross-border operations are far less momentous than oper-

ations that seek to topple adejure government (as occurred when the United States

intervened in Iraq in 2003, ousting the government of Saddam Hussein) or ade

facto government (as occurred when the United States intervened in Afghanistan

in 2001, displacing the largely- unrecognized government of the Taliban). Never-

theless, these smaller-scale cross-border attacks on non-State actors, though they

entail less intrusive and more temporary projections of force, implicate important

issues of sovereignty, stability, and self-defense, and raise difficult questions about

the role of law in regulating low-intensity conflict.

This article discusses the nature of these cross-border operations for the pur-

pose of assessing their legality under the jws ad bellum, meaning their consistency

*Patricia Roberts Harris Research Professor of Law, George Washington University Law School.

The International Legality of US Military Cross-Border Operations

with the norms embodied in Articles 2(4) and 51 of the UN Charter. Attention is

devoted to unpacking the complicated and evolving circumstances on the

ground, but the facts at issue in many instances are quite difficult to discern, and

hence can support only tentative legal conclusions. While the focus here will

principally be on US operations from Afghanistan into Pakistan from 2002 to

the present, the analysis is relevant in other contexts as well, such as Turkey's

cross-border operations in northern Iraq against the Kurdistan Workers' Party or

Colombia's recent forays into Ecuador against the Revolutionary Armed Forces

of Colombia.

Among other things, this article assumes that analyzing the legality of US cross-

border operations into Pakistan under the jus ad bellum is important to the United

States. US law and policy generally call for compliance with international law in the

conduct of US military operations. Further, US ability to secure the cooperation of

other States may turn on whether US operations are in compliance with interna-

tional law. Support from US allies includes support from Pakistan itself, in that most

cargo and much fuel supporting the approximately thirty thousand US forces that

are based in landlocked Afghanistan transit through Pakistan. 1Indeed, in September

2008, the Pakistani government threatened to close down US supply routes into

Afghanistan in response to US cross-border operations, prompting the United

States to rethink its strategy in this area. 2Broader US objectives of maintaining a

stable Pakistan—an objective arguably paramount for the United States in com-

bating terrorism3—may turn in part on internal Pakistani perceptions concerning

the legality of US conduct. Moreover, though adjudication of the legality of US

cross-border operations before an inter-State tribunal, such as the International

Court of Justice, may not be likely, it is not impossible, and adverse rulings may af-

fect the ability of the United States to maintain both domestic and international

support for its policies.4Finally, the State parties to the Rome Statute 5establishing

the International Criminal Court (ICC), at their review conference in 2010, may

activate the ICC's jurisdiction over the crime of aggression, thereby potentially ex-

posing US military personnel engaged in such cross-border operations to interna-

tional criminal liability.6For all these reasons, there is value in assessing the legality

of US cross-border operations against Pakistan under the jus ad bellum.

US Cross-Border Operations from Afghanistan to Pakistan

The Afghan-Pakistan Border in Law

The 2,250-kilometer-long border between Afghanistan and Pakistan was essen-

tially established in 1893 by Sir Henry Mortimer Durand, acivil servant and diplomat

of colonial British India. The purpose of the line (which became known as the

110