Due to the history of British rule, it's unlikely the Republic would ever have entered into a borderless common trade zone with the UK on it's own.Why ?....
I believe that a lot in the Republic voted to give up articles 2 and 3 of the constitution as the growth of the European common market made isolationist policies less desirable.
Using the EU as a common third party seems to have been the key to eliminating an militarized border as well as a trade border.
It is my fear that Brexit will lead to a reinstatement of a trade border which will, in time, lead to a reinstatement of a militarized border.
I hope I'm wrong.
