By: Michael T. Moran
By now, international observers are well aware of the notorious one-line tweet seen around the world: “Mexico will pay for the wall!” Following his inauguration on January 20, 2017, American President Donald Trump pledged to undertake his campaign promise that involves constructing an immigration wall along the American-Mexican border, with Congress initially funding the project and “then find[ing] ways to have Mexico reimburse those costs later.” In having Mexico pay for the wall, the Trump administration has suggested imposing increased taxes on imported goods to the United States from Mexico. In response to President Trump’s plan, former Mexican President Vicente Fox Quesada proclaimed, “Neither today, nor tomorrow nor never Mexico will pay for that stupid wall. If Trump wants a monument to his ego, let him pay for it!!” Mexico’s foreign secretary noted that President Trump’s wall construction plan is “a matter of national dignity and sovereignty.” Moreover, Mexico’s current economic conditions raise concerns that the country would even be able to pay for the wall, which would be “political suicide” for the country’s current president, Peña Nieto.
Plans implicating the construction of a wall along the United States-Mexico border in order to combat illegal immigration into the United States is not by any means an emerging political phenomenon. However, President Trump’s stern and aggressive demeanor regarding the construction and funding for the wall has “so deeply antagonized the Mexican populace.” Andres Manuel López Obrador, a leading leftist candidate for the Mexican presidency in 2018, “urged his government to lodge a lawsuit against U.S. President Donald Trump at the United Nations” because the wall is “an insult to his country” and violates human rights.
Moreover, both the United States and Mexico are signatory members to the United Nations. With respect territorial sovereignty, the Charter of the United Nations dictates that “[a]ll Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.” Additionally, the Mexican Constitution states, “The national sovereignty is vested, originally and essentially, in the [Mexican] people,” and that “the Mexican people … [make] up [the] free and sovereign States.”
With a foreign nation (i.e., the United States) positing the idea of having Mexico finance the construction of an immigration wall that would not be within Mexican borders, Mexico’s territorial sovereignty would arguably be unduly encroached upon if a wall is built and Mexico eventually pays for it. In turn, Mexico would be economically and politically pressured into funding a border wall that it has repeatedly asserted not wanting any role or responsibility in constructing. Therefore, this enterprise on part of the Trump administration is potentially a violation of international law and the national sovereignty provisions enumerated in the Mexican Constitution.
Article 2(4) of the Charter of the United Nations
The phrase that all United Nations signatory members must refrain “from the threat or use of force against the territorial integrity … of any state” is facially ambiguous because the Charter of the United Nations fails to provide a definition for what constitutes a “use of force.” Upon review of the provision, Article 2(4) aims to “protect the territorial integrity and political independence of sovereign States” through the use of armed military force. However, records from the San Francisco conference—where the Charter of the United Nations was drafted—show that Article 2(4) was written to be construed “in the broadest terms [and be] an all-inclusive prohibition without loopholes.”
In fact, scholars have noted that “[b]y not specifying the denotation of the concept of ‘force,’ those who drafted the Charter left the meaning of [A]rticle 2(4) vulnerable to whatever connotation the word has in the minds of those reading it.” Moreover, legal scholarship analyzing Article 2(4) argue that the ambiguity surrounding the term “force” denotes the drafters’ intention a broad interpretation. A liberal interpretation would likely render the term “force” to be extended to economic coercion along with the traditional prohibition against unjustified military force. Economic coercion entails “boycotts, embargoes, or attempts by rival nations to f[r]eeze the victim-state’s assets or dry up its markets on a global scale.” Against this backdrop concerning the vagueness and unclear meaning of Article 2(4)’s prohibitions, United Nations member states must “realize … that economic and political coercion, like military coercion, can impair the target State’s sovereignty and create the kinds of feelings of which international fear and tension are made.”
Applying Article 2(4) to the United States-Mexico Border Wall Context
In applying a broad interpretation of Article 2(4) of the Charter of the United Nations, the American government is “threat[ing] [the] use of force against the territorial integrity [and] political independence” of the sovereign Mexican state. If a border wall is built and the United States somehow compels Mexico to “pay for it through reimbursement,” Mexico’s territorial integrity and political independence with respect to making national economic decisions will be unjustifiably intruded upon. Even if Mexico does not directly pay for the immigration wall, President Trump’s administration has suggested a 20 percent border tax on Mexican goods imported to the United States to recoup construction expenses, which will also adversely influence Mexico’s ability to make national economic decisions.
If Mexico reimburses the United States for the immigration wall via an increased border tax, this could classify as an act of economic coercion, which could in turn “dry up [Mexico’s] markets on a global scale.” Referring to the “principle[s] of national sovereignty and dignity,” the Mexican foreign minister stated, “As the government of Mexico has always maintained, our country will not pay, in any way or under any circumstances, for a wall or physical barrier built on US territory along the Mexican border.” In making this statement, Mexico has unilaterally decided to refuse to fund a wall that will not be built within its territory, especially considering the country’s stagnant economic conditions.
Mexico’s current situation concerning President Trump’s border wall has undoubtedly created a hostile political environment between the neighboring nations. From a legal perspective, however, international law via the Charter of the United Nations mandates that all member states must honor territorial integrity and political independence. The definition of “use of force” in the Charter of the United Nations remains ambiguous, as legal scholars continue to argue for and against the broad interpretation of the phrase, which was left undefined by the Charter’s drafters. Broadly speaking, the argument could be made that Mexico can be economically coerced into financing the border wall through the implementation of border taxes, thereby detrimentally impacting Mexico’s territorial integrity and national economy. Mexican officials have incessantly asserted that Mexico will not finance the border wall, emphasizing the country’s territorial integrity and desire not to pay for a wall that will not be constructed within its borders. Therefore, Mexican demands for a United Nations lawsuit against the United States for violating the Charter of the United Nations do not appear to be as farfetched as news articles present the issue.
 Donald J. Trump (@realDonaldTrump), Twitter (Sept. 1, 2016, 3:31 AM), https://twitter.com/realdonaldtrump/status/771294347501461504?lang=en.
 Kate Linthicum & Kurtis Lee, Trump Still Says he’ll Make Mexico Pay for his Border Wall, but Can he Really?, L.A. Times (Jan. 12, 2017, 2:05 PM), http://www.latimes.com/world/mexico-americas/la-fg-trump-mexico-wall-20170111-htmlstory.html.
 Vicente Fox Quesada (@VicenteFoxQue), Twitter (Jan. 11, 2017, 9:15 AM), https://twitter.com/vicentefoxque/status/819231300829794304?lang=en.
 Linthicum & Kurtis Lee, supra note 2.
 See Secure Fence Act of 2006, Pub. L. No. 109-367, 120 Stat. 2638-2640.
 Azam Ahmed, As Trump Orders Wall, Mexico’s President Considers Canceling U.S. Trip, N.Y. Times (Jan. 25, 2017), https://www.nytimes.com/2017/01/25/world/americas/trump-mexico-border-wall.html.
 Anahi Rama, Mexico Opposition Leader Urges U.N. Lawsuit Over Trump Wall, Reuters (Jan. 25, 2017, 8:27 P.M.), http://www.reuters.com/article/usa-trump-mexico/mexico-opposition-leader-urges-u-n-lawsuit-over-trump-wall-idUSL1N1FG01T.
 History of the Charter of the United Nations, U.N., http://www.un.org/en/aboutun/charter/history/declaration.shtml (last visited Oct. 24, 2017).
 U.N. Charter art. 2, ¶ 4 (emphasis added).
 Constitución Política de los Estados Unidos Mexicanos, CP, art. 39, Diario Oficial de la Federación [DOF] 05-02-1917, últimas reformas DOF 10-02-2014 (Mex.).
 Id. at art. 40.
 Nico Schrijver, The Use of Force Under the UN Charter: Restrictions and Loopholes, Acad. Council on the U.N. Sys., http://acuns.org/wp-content/uploads/2012/09/WebPageSchrijver_UseofForce.pdf (last visited Oct. 24, 2017).
 Comment, The Use of Nonviolent Coercion: A Study in Legality Under Article 2(4) of the Charter of the United Nations, 122 U. Pa. L. Rev. 983, 987 (1974).
 Id. at 988.
 Id. at 991.
 Id. at 1010–11 (emphasis added).
 U.N. Charter art. 2, ¶ 4.
 Donald J. Trump (@realDonaldTrump), Twitter (Aug. 27, 2017, 6:44 AM), https://twitter.com/realDonaldTrump/status/901802524981817344?lang=en.
 Catherine E. Shoichet, Sergio Hernandez & Tal Kopan, Three Ways Mexico Could Pay for the Wall, CNN (Mar. 29, 2017, 9:42 AM), http://www.cnn.com/2017/03/29/politics/can-mexico-pay-for-wall-trnd/index.html.
 The Use of Nonviolent Coercion: A Study in Legality Under Article 2(4) of the Charter of the United Nations, supra note 17, at 991.
 Margaret Talev, Trump Repeats Making Mexico Pay for Wall as he Seeks Funding, Bloomberg Pol. (Aug. 27, 2017, 10:57 AM), https://www.bloomberg.com/news/articles/2017-08-27/trump-recommits-to-make-mexico-pay-for-wall-as-he-seeks-funding (emphasis added).
 See Linthicum & Lee, supra note 2.
 See U.N. Charter art. 2, ¶ 4.
 See generally The Use of Nonviolent Coercion: A Study in Legality Under Article 2(4) of the Charter of the United Nations, supra note 17, at 1010–11.
 See Linthicum & Lee, supra note 2.
 See Rama, supra note 9.