Is revoking citizenship for affiliation with a terrorist group a violation of international law?
<p>In two very notable recent cases, <a href="https://www.nytimes.com/2019/02/20/world/middleeast/isis-bride-hoda-muthana.html" rel="noreferrer">Hoda Muthana of the US</a> and <a href="https://www.bbc.com/news/uk-47299907" rel="noreferrer">Shamima Begum of the UK</a> were stripped of their citizenships by their respective countries of origin while attempting to return after leaving years earlier to join ISIS. But is it legal?</p>

<p>The <a href="https://en.wikipedia.org/wiki/Convention_on_the_Reduction_of_Statelessness" rel="noreferrer">1961 Convention on the Reduction of Statelessness</a> and the <a href="https://en.wikipedia.org/wiki/Convention_relating_to_the_Status_of_Stateless_Persons" rel="noreferrer">1954 Convention relating to the Status of Stateless Persons</a> before it, at least one of which was signed by most major western countries, lay out a framework for reducing statelessness and improving the lives of those who find themselves stateless. One of the core tenets of these treaties, as stated in Article 15 of the <a href="http://www.un.org/en/universal-declaration-human-rights/" rel="noreferrer">Universal Declaration of Human Rights</a>, is that "Everyone has the right to a nationality".</p>

<p>It is worth noting that the United States is not a party to either of these treaties, and further claims that Hoda Muthana was never a citizen as her father was a diplomat. Further research indicates she was born a month after his diplomatic status ended and there seems to be documentation of her possession of citizenship documents, but that's politics. The UK case is far more cut-and-dry.</p>

<p><strong>So... if <a href="https://www.refworld.org/docid/54576a754.html" rel="noreferrer">a nation party to one or both of the Statelessness Conventions</a> revokes one's citizenship because of affiliation with a terrorist group, is that allowed under the terms of the Statelessness Conventions, or is it a violation of international law?</strong> </p>

<p>Insofar as those treaties don't bind the US, the notion of "violating" such laws is moot. Hoda Muthana is, under Yemeni law, a Yemeni citizen (it is immaterial whether she has ever "accepted" or exploited it), and as such stripping her of US citizenship would not leave her stateless.</p>

<p>In the case of Hoda Muthana, the action is based on the legal argument that she was not ever a citizen, based on the premise that her father was a foreign diplomat. Under US law, children born to foreign diplomats in the US are not birthright citizens, following <a href="https://www.law.cornell.edu/supremecourt/text/169/649" rel="nofollow noreferrer">US v. Wong Kim Ark</a>. Birthright citizenship cannot be revoked. However, a person can <a href="https://www.law.cornell.edu/uscode/text/8/1481" rel="nofollow noreferrer">renounce their citizenship</a>, via certain acts, including</p>

<blockquote>
  <p>taking an oath or making an affirmation or other formal declaration of
  allegiance to a foreign state or a political subdivision thereof,
  after having attained the age of eighteen years;or</p>
  
  <p>(3) entering, or serving in, the armed forces of a foreign state if
  (A) such armed forces are engaged in hostilities against the United
  States, or (B) such persons serve as a commissioned or
  non-commissioned officer</p>
</blockquote>

<p>The defense argument would presumably be that ISIS is not a foreign state (despite their own claims to the contrary) so her affiliation with ISIS does not qualify.</p>

<p>There are grounds for <a href="https://www.law.cornell.edu/uscode/text/8/1451" rel="nofollow noreferrer">denaturalization</a>, including falsifying or concealing relevant facts pertaining to naturalization, refusing to testify before Congress, or joining a subversive organization including Al Qaeda within 5 years of naturalization.</p>

<p>I believe that, generally, who is a country's national or citizen is solely determined by the law of that country, and there is no general "international law" regarding revoking citizenship. There is that Convention on the Reduction of Statelessness, and countries that are party to it agree to not revoke citizenship if it would make the person stateless (unless the citizenship was obtained through fraud or a few other exceptions), and not let someone renounce citizenship if it would make them stateless. I don't think that the Convention says anything about the reasons citizenship can be revoked if it doesn't make one stateless. Only a minority of countries in the world are party to that Convention. For the countries you mentioned, the UK is a party to the Convention, but the US is not.</p>

<p>In the case of the UK, British law already largely incorporates the requirements of the Convention regarding revoking of citizenship. So if the UK follows its own law, it should not violate the Convention. Although <a href="https://www.legislation.gov.uk/ukpga/1981/61/section/40" rel="nofollow noreferrer">section 40</a>(2) of the British Nationality Act 1981 (as amended) allows the Secretary of State to deprive a British citizen of British citizenship:</p>

<blockquote>
  <p>(2) The Secretary of State may by order deprive a person of a
  citizenship status if the Secretary of State is satisfied that
  deprivation is conducive to the public good.</p>
</blockquote>

<p>section 40(4) restricts it to only dual nationals:</p>

<blockquote>
  <p>(4) The Secretary of State may not make an order under subsection (2)
  if he is satisfied that the order would make a person stateless.</p>
</blockquote>

<p>(Though it should be noted that section 40(4A) provides a slightly looser restriction on deprivation of citizenship of <em>naturalized</em> British citizens -- their citizenship can be deprived even if it will them stateless, as long as they are able to become national of another country. I am not sure if this provision complies with the Convention. In any case, this is not relevant to Shamima Begum's case as I don't think she's a naturalized citizen.)</p>

<p>In Shamima Begum's case, the issue is with whether she has another nationality or not. The British government is claiming that she does, and she is claiming that she doesn't. If she really doesn't have another nationality, then she can already challenge the deprivation of her British citizenship as violating British law, and she doesn't need to invoke the Convention or international law.</p>

<p>The US is not a party to the Convention, but US citizenship cannot be "revoked" in the same way that British citizenship can. Loss of US citizenship is provided in <a href="https://www.law.cornell.edu/uscode/text/8/1481" rel="nofollow noreferrer">8 USC 1481</a>(a), but only if the person commits one of several "potentially expatriating acts" "with the intention of relinquishing United States nationality", and the standard of evidence is "preponderance of evidence" according to 8 USC 1481(b). It would be necessary to prove that the person intended to relinquish US citizenship to revoke their US citizenship, and not just for "the public good" or because they committed some crime or other bad act in itself. (On the other hand, the US does allow you to voluntarily renounce US citizenship even if it would make you stateless (see <a href="https://fam.state.gov/FAM/07FAM/07FAM1210.html#M1215" rel="nofollow noreferrer">7 FAM 1215</a>(e) and <a href="https://fam.state.gov/FAM/07FAM/07FAM1260.html#M1261" rel="nofollow noreferrer">7 FAM 1261</a>(g)), which it wouldn't be able to allow if it were a party to the Convention.) None of this is really relevant to the case of Hoda Muthana, because in that case the US isn't claiming that she lost US citizenship at all -- but rather that she was never a US citizen in the first place because she was born to a diplomat.</p>

international citizenship stateless