Is it time to join Nato

The problem with this line of thinking is that it is reliant upon two very large assumptions.

1) That the likes of the UK, other EU states and US aren't already occupied dealing with a threat to their actual allies. If Norway is fighting for its territory (on the basis that the declared purpose of the Norwegian defense forces isn't to protect against invasion as much as to try to hold on as much as possible before allies such as the UK, other NATO states and the US show up), they're going to leave Ireland for a 'when we can get around to it' situation and prioritise other problems. Doubtless they will eventually get around to it, but it'll take some time.

2) That in the period of time that the UK, other EU states and the US actually do get around to coming to Ireland's aid, the citizens of Ireland will be quite happy with the any localised occupation or battles going on on their territory. It's not like Ireland would ever be occupied a la Belgium or Norway in WW2, but specific useful areas like Shannon airport might be objectives. We have recent evidence from a number of conflicts that the presence of hostile troops does not always result in a positive experience for local civilians.

There is also a knock-on effect perhaps not being considered: Ireland's prosperity is directly linked to that of its trading partners, particularly in the EU. NATO warships keeping an eye on Irish waters cannot be in the Baltic or North Atlantic at the same time. What additional damage may a Baltic country suffer because forces which would otherwise be available to NATO had Ireland the capability to look after its own interests were not present? What additional costs in lives, time and rebuilding Euros would the EU economy have to expend before Ireland's economic position, which would include trade, would return to a pre-conflict level?

Marching to Belfast is pretty daft, it would provide no particular advantage, certainly not worth the effort. People thinking that Ireland would become this big red blob on the map next to the UK in order to threaten invasion from the West have entirely the wrong idea. Not even the Russians would have the manpower to do that. Controlling discrete areas like Knock or Shannon airports, or Foynes port, however, is a far more realistic option which could have an outsized effect on the lines of communication from North America to Europe without any need to attempt to occupy an entire country, or even a single city. Unless anyone thinks the Russians in 2035 will fully believe that they don't need to intercept the powerhouse of North American manpower or industry in order to win, but I certainly wouldn't make that assumption.

I agree, NATO would not leave it alone, but I believe we differ on the nature of both the problem and the response. If Ireland were to be used for the one thing it is really useful for, i.e. controlling traffic across the Atlantic, NATO wouldn't just sit by. One could expect repeated attacks on occupied infrastructure, to destroy Russian capability. The US wouldn't be sending the 82nd Airborne to liberate the place, but they will certainly be sending missiles and bombs to blow it up as a much easier way of attaining a similar result. I don't foresee that as being particularly any more beneficial to people who live or work around there than being under the control of an occupying force.