The Prime Minister, Boris Johnson, told Westminster yesterday that his Government "will have no hesitation in invoking Article 16" of the Ireland/Northern Ireland Protocol "if there are problems that we believe are disproportionate" in its operation.
His assurance came in response to a question from Sir Jeffrey Donaldson outlining some of the difficulties that have been encountered in the movement of goods across the Irish Sea since the end of the Brexit transition period.
And these are early days yet. Could Article 16 really be a magic bullet to fix the so-called Irish Sea border?
Article 16 of the Protocol is about "safeguards" and the mechanism for putting them in place. Such safeguards are often found in trade agreements.
A similar provision is included, for example, in Article 112 of the Agreement on the European Economic Area. Such measures are, however, rarely used. This is because the bar for invoking them is necessarily high.
The purpose of safeguards is to create a temporary breathing space to resolve serious issues arising out of the implementation of an agreement. Their purpose is not to set aside, or revoke, the agreement.
On the contrary, safeguards are intended to avert a major crisis in a way that ultimately secures the operation of the agreement for the longer term.
Article 16 is one of the last provisions of the Northern Ireland Protocol; it is best thought of as a last resort. The necessary assumption is that, having negotiated the Protocol, both sides are committed to its application.
And so, if there are problems arising from its operation, these are to be raised, in the first instance, through the proper channels - in this instance, the Specialised Committee, which then should make recommendations to the UK-EU Joint Committee.
A key purpose of these joint bodies is to find agreed UK-EU responses to difficulties in implementing the jointly agreed Protocol.
What is distinct about Article 16 is that it permits the UK and the EU to act unilaterally, but only where the application of the Protocol is leading to "serious economic, societal or environmental difficulties" that are "liable to persist".
Article 16 does not specify what constitutes a "serious" difficulty. Nor does it define what constitutes a "diversion of trade" - the second justification provided for adopting safeguard measures.
However, as safeguards, such measures are not intended to address either temporary disruptions, or reasonably foreseeable challenges.
If the UK, or the EU, does deem it necessary to adopt unilateral safeguard measures, Article 16 is clear that these are to be "restricted with regard to their scope and duration" and to what is "strictly necessary" to address the difficulty, or difficulties, being faced. The overall intention of any safeguard is that it "disturbs" the functioning of the Protocol as little as possible.
Article 16 is not, therefore, a route to the unilateral disapplication, or suspension, of the Protocol. Even if it were triggered, the Protocol's provisions continue to apply and this includes those on monitoring and enforcement.
Furthermore, if one side does introduce unilateral safeguard measures, the other may adopt "rebalancing" measures.
If it were to invoke Article 16, the UK Government would need to be clear about three things. What are the serious difficulties and what specific measures would it propose to address them? How would those unilateral actions be necessary and preferable to solutions agreed with the EU? And what would be the likely EU re-balancing measures and would this be a risk worth taking?
The UK Government should also be clear that this is no "quick fix". Annex 7 of the Protocol sets out the process to be followed when invoking Article 16.
First, if either party is even "considering" unilaterally adopting safeguard measures, it must notify the other party "without delay" and through the Joint Committee. Consultations between the two sides follow.
Only if a common solution cannot be found can safeguards be adopted (normally only after a further three months).
Also, safeguards must be strictly limited in their scope and duration. Even when triggered, the UK-EU Joint Committee will monitor their application with a view to abolishing them as soon as possible.
Article 16 is a "big red button" that exists for good reason. But those calling for its use should be absolutely clear about what it can and cannot do.
It is certainly not a quick fix, nor is it a get-out clause from the realities of Brexit and the Protocol.
To invoke it in the wrong conditions could give rise to far greater problems than those it would seek to address.
Katy Hayward is Professor of Political Sociology at Queen's University, Belfast and Senior Fellow at the UK in a Changing Europe think-tank. David Phinnemore is Professor of European Politics in the School of History, Anthropology, Philosophy and Politics at Queen's. This is a shorter version of an article originally published on the Brexit blog of the London School of Economics