It’s a third of those who voted in referendum and bigger proportion of the target demographic which is rural SF and FF.
He has said, according to media, that members will be allowed a free vote on issue. A party just focused on abortion either way would be doomed to failure. Ultra left can be extreme about it as that’s the sort of demographic and ideological creature they appeal to, and they are basically limited to a small proportion of the electorate. .
I suspect FF and SF will pay some price for their stance. A leftish republican party on prolife side has way more potential than Renua. That’s if it gets off the ground and the history of smaller parties is not great.