A major obstacle in the Brexit negotiation process currently is the issue of the Irish border. All available options seem insufficient to some or all of the negotating partners, as detailed in this answer to another question:
The UK government now has four basic options to choose between:
- Remain part of the EU single market, accepting EU rules and regulations, but without the seats in the EU parliament and other decision-making parts of the EU...
- Implement a "hard border" between Northern Ireland and the Republic...This is not acceptable to the Irish Republic or the EU. It is also something that the UK government previously promised the EU that it would not do.
- Implement an equivalent border in the Irish sea between Northern Ireland and the mainland UK, and keep Northern Ireland in the European common market...
- The "Singapore model": abolish all import controls and duties on any goods from anywhere (anything more selective would run foul of WTO rules)...
This answer concurs, stating that:
There is simply no way that status quo can be upheld between the UK, Northern Ireland and the Republic of Ireland if the UK leaves the Single Market.
However, a recent article in The Irish Times proposes that the claim against the possibility of implementing selective rules (which I have emphasised above) is not entirely true, arguing that
there are exceptions to the scope of the WTO rules, including most importantly the “national security exception,” article 21 of the general agreement on tariffs and trade (Gatt): “Nothing in this agreement shall be construed . . . to prevent any contracting party from taking any action which it considers necessary for the protection of its essential security interests . . . taken in time of war or other emergency in international relations.”
The authors cite President Trump's use of the same exception when introducing country-specific tariffs. Presumably, therefore, the powers that be are not unaware of this exception. They also outline the potential benefits to both the EU and Ireland of agreeing to such a soft land border, and it seems that doing so would satisfy all of the interests otherwise not served by the exisiting four options.
With all that in mind, why is this not being widely proposed as a desirable fifth option? Is there some obstacle not mentioned in the article, or is this exception not as widely known as it should be?