What did it used to mean when Sinn Fein threatened with "grave implications"?

Question

I don't claim to have a deep understanding of Northern Ireland politics. I found it fairly ominous that in a recent declaration (19 March 2019) a Sinn Fein vice-president said:

"The British Government and Michael Gove, a long-term opponent of the Good Friday Agreement, are playing to the unionist demand for unrestrained British direct rule.

"I cannot overstate the grave implications if the British Government follows through on these threats."

Were "grave implications" some kind of coded language for specific actions in Sinn Fein's past?

Answer 1

"The British Government and Michael Gove, a long-term opponent of the Good Friday Agreement, are playing to the unionist demand for unrestrained British direct rule."

To answer the question it's important to clarify that direct rule means Northern Ireland being governed directly by the UK government. In 1998 the Good Friday Agreement ended 26 years of direct rule in Northern Ireland (although there were temporary periods of time when direct rule was reinstated since).

Among other things, the Good Friday Agreement establishes specific power-sharing mechanisms for the governance of NI. For example under certain circumstances a cross-community vote can be required at the NI Assembly, to ensure that neither nationalists nor unionists can decide something against the will of the other community. Obviously direct rule breaches this subtle balance of power decided by the Good Friday Agreement in favor of the unionists, therefore nationalists would probably consider that it invalidates the agreement.

"I cannot overstate the grave implications if the British Government follows through on these threats."

Although the threat is implicit, one can easily understand what kind of "grave implications" would be caused by the Good Friday Agreement being invalidated: some nationalists would be tempted to take arms again, against what they would see as an illegitimate colonial power.

[Edit to answer the question clearly] It's not coded language, it's a threat from the main nationalist party to declare the Good Friday Agreement dead in the water. Everyone who understands that the Agreement was what stopped the violence can deduce that this would be likely to cause "grave implications", indeed.

Answer 2

I don't claim to have a deep understanding of Northern Ireland politics.

Same here, but I'll attempt an answer anyway. So, your quote comes directly from Sinn Fein's website, here. The title of that article is as follows:

British Government has abandoned any pretence of impartiality - Michelle O’Neill MLA

From that and your quote it's clear that Sinn Fein does not want direct rule. The article ends with the following:

“The Irish Government has a responsibility as a co-guarantor of the Good Friday Agreement to oppose any attempt by the British Government to act unilaterally break joint international agreements.”

Now we know where to look, the grave implication seems to be that direct rule might be in conflict with the GFA.

Looking into the combination of 'GFA' and 'direct rule', we find an opinion peace by mister Fitzgerald (apparently, a former football player) in The Irish News. In that piece, he wrote the following:

Any measures by London to bring back direct rule could legally be construed as invalidating the GFA. The GFA is a contractual and constitutional document which is designed to replace direct rule. Because it has been frustrated in its workings on power sharing, it could even now be discharged notwithstanding the declared imposition of direct rule by the secretary of state. Given the long multiple suspensions of the GFA, anybody could potentially claim that devolution is no longer in effect in Northern Ireland. It is only in effect if there is power sharing which has now become frustrated. Legally one could also argue that direct rule is already in effect by default – in default of the GFA.

For obvious reasons, the GFA is important for peace in Northern Ireland, and the suggestion that the peace will be ended is very worrisome.

Answer 3

End of "The Troubles" was conditional on GFA

For any discussion of the Good Friday Agreement it's important to look at the main reason for it, which is the The Troubles - a prolonged, bloody, violent conflict that caused more than 3500 deaths and many more injuries.

GFA is essentially a cease-fire agreement. It's not an agreement which you can simply "leave" like the EU treaties. To be blunt, unilaterally breaking the conditions of such a cease-fire agreement implies a return to hostilities. The cease-fire was signed not that long ago, and it's certainly not yet faded into ancient memory, it's not (yet?) became obsolete. There are people who were ready to spill blood to get the terms of GFA but were willing to temporarily lay down their arms due to GFA. Many of these people are still alive today and many of them hold the same convictions.

The commitment to not impose direct rule on NI comes together with the commitment not to bomb people in London and Belfast. Take away one and you lose the other - that's a pretty clear and obvious grave implication. If one side considers appropriate to resume security checkpoints on border of NI and RI, then it is plausible that some people on the other side might consider appropriate to resume killing the people manning such checkpoints.