How did a character like Charles Haughey become taoiseach?

What was it about Ireland in the 1970s and 1980s that a man like Charles Haughey could become its leader? Did he improve the country, despite the corruption? And how did Garrett FitzGerald make such a mess of the abortion question?
Following our recent podcast series on the era-defining rivalry between Charlie Haughey and Garrett FitzGerald, Hugh Linehan and Pat Leahy return to the subject one last time, taking on listener questions they received via email and social media.