The people elect the parliament, by PR; and the parliament elects the government, by PR. Otherwise you get those crazy consequences of majoritarianism: the US Republicans hoping that Obama will fail; the UK Labour Party producing a budget of debt deisgned for only one year.
In Ireland, too, the need for parliamentary collective responibility is obvious. Hence this letter in The Irish Times, published on Wed. 22nd April.
(See also 2012-7 and 2011-6/5.)