In my opinion if the referendum is passed, legislation will be introduced and the whole issued will largely disappear from the public agenda. Those who will remain opposed to abortion will not be able to overcome the general feeling that the issue has been resolved.
If the referendum is not passed, the issue will remain on the public agenda, we can expect to see a rerun in some form or other within a few years.
It won't. The legislation still has to pass even if the referendum passes. Every TD in the country will come under local pressure. The party whips will be out but there will be political casualties. I can guarantee that the published legislation will not be the final legislation. If the referendum fails to carry, there will not be another referendum for very long time. There is no political gain in revisiting it.