There was been a number of threads where the objective seems to be to get RoI into world war 2 on the side of the allies. I think all of them come at it from the angle of Ireland declaring war. I don't think that's very feasible however what if its Germany to declare war first? The PoD I have in mind is April 1941 when the Germans demand not just that RoI do not assist Belfast again after it was bombed bu also that it stops all supplies of food to the UK which is refused? That impact would it have of the war, specifically the Battle for the Atlantic but also post war and Irish membership of NATO?
It's a really pointlessly stupid thing to do but, well, Hitler.
Once the puzzlement recedes the following happens:
1. There is a complimentary Declaration of War against Germany as soon as the DEA figures out the procedure.
2. A visit to the USA to discuss assistance, complete with lots of reaching out to the Irish American Democrat block
3. Rather less enthusiastic talks with the UK, especially regarding ASW cooperation and air defense
4. Internment of quite a number of people who hadn't already been locked up. Just In Case...
In the medium term I'd expect
1. Much US aid and the total rebuilding of the Defense Forces
2. A significant diminution of German submarine and maratine patrol effectiveness in the Atlantic.
3. An Irish DoW against Japan after the attack on Pearl. Possibly some nominal assistance but a massive propaganda campaign to get Irish Americans to assist with the war. Probably not really needed.
4. US military bases in Ireland. Back to Whiddy, Lough Foyle, Cobh, Berehaven and Wexford? And Shannon of course.
5. A massive economic boost when US forces started arriving in numbers. And the resurrection of the Monto...
Longer term.
After the war de Valera won't be able to re-cork the genie. Significant social and economic change, perhaps an earlier loss of power for Fianna Fail? Ireland in NATO is entirely possible, the US was always interested in Shannon.