Party dominated previous elections
Fianna Fail candidates have topped the poll in every presidential election.
Only Mary Robinson for the Labour Party in 1990 has beaten Fianna Fail.
Fianna Fail won the election with Sean T O Ceallaigh in 1945, Eamon de Valera in 1959 and 1966, Erskine Childers in 1973 and Mary McAleese in 1997.
Cearbhall O Dalaigh in 1974 and Dr Patrick Hillery in 1976 were appointed without a contest.
The first president, Douglas Hyde, was a cross-party nominee in 1938.