 If there are no other nominations, no election is required, however the Australian Greens in 2005 and again in 2007 put forward Senator Kerry Nettle as a rival candidate when the position of President was vacant.Neither Government nor Opposition Senators supported that candidacy.The President's principal duty is to preside over the Senate, to maintain order in the Senate, uphold the Standing Orders (rules of procedure) and protect the rights of backbench Senators.