Why was it so easy for Northern Irish parties to betray their voters on abortion?

It’s unfortunately the case that just because a person opposes abortion does not mean that opposition to abortion is a political priority for them. Hard as it may be to believe for many of us convinced pro-lifers, a person may oppose abortion but care far more about other political issues, and not be particularly inclined to vote on the the issue in politics. That’s why we’re not seeing the NI parties pay a political cost.