Since the leadership was vacant, a contest required the nomination of only two candidates. Under the rules in force, win in the first round, a candidate not only needed to win the backing of an absolute majority of members of parliament, but also needed a majority over the runner-up of 15 per cent of the total electorate. If neither of these were achieved, then a second ballot would take place in the following week, nominations would be reopened, and at this stage an absolute majority only would be required to win. If there were no winner on the second ballot, then the top two candidates would go forward to a third round.