Complex sentence: Social liberals made gains in most of these areas; with the exception of abortion; leading Barrett to the conviction that political involvement was necessary for results-he was subsequently involved in Young Fine Gael until 1991.
Split into simpler sentences: Social liberals made gains in most of these areas, with the exception of abortion; this led Barrett to the conviction that political involvement was necessary for results. He was subsequently involved in Young Fine Gael until 1991.