GATT Article XXIII:1 sets out the following types of complaints:
If any contracting party should consider that any benefit accruing to it directly or indirectly under this Agreement is being nullified or impaired or that the attainment of any objective of the Agreement is being impeded as the result of
(a) the failure of another contracting party to carry out its obligations under this Agreement, or
(b) the application by another contracting party of any measure, whether or not it conflicts with the provisions of this Agreement, or
(c) the existence of any other situation,
We all know about the "nullified or impaired" language. But what about the "attainment of any objective of the Agreement is being impeded" language? Is that ever going to be used in a WTO complaint? What would such a complaint look like? The terms are pretty vague, which could give rise to some creative legal arguments, such as this one by Alexia Herwig:
I argue that the WTO’s non-violation and situation complaints for impediments to the attainment of treaty objectives (hereafter collectively referred to as impediments-to-attainment-of-objectives complaint or IAOC) require members to account for extraterritorial impacts on standards of living created through trade in goods.
As the objective of the WTO and GATT is to improve access to food, clothing, shelter and possibly other relevant items through means of trade, a situation where trade in goods durably worsens standards of living of any individual, is one in which the attainment of the objective of the GATT is impeded because it is in direct opposition to the goal stipulated in the preamble. The ICESCR [International Covenant on Economic, Social and Cultural Rights] could also be used as context to interpret the IAOC to encompass situations where trade results in individuals falling below an adequate standard of living. We could consider WTO law to be an effort at cooperation aimed at respecting, protecting and fulfilling the right to an adequate standard of living as in Article 11.1 ICESCR, so that its interpretation should be maximally compliant with the ICESCR. The Maastricht Principles also affirm that there is an obligation of states to elaborate, apply and interpret international trade agreements consistently with their human rights obligations.
More details at the link.
To be clear, I'm not saying I think the provision should be used this way; just highlighting a creative argument. More generally, it's worth emphasizing that the provision in question is just sitting out there, waiting to be invoked some day. What are the circumstances under which this might happen?