Anne Twomey writes in The Conversation (9.5.18) that the High Court decision against Labor senator Katy Gallagher has clarified how to interpret the constitution on this matter; but the problem of dual citizenship can only be properly fixed by a referendum.
'In one fell swoop, the High Court's judgment about the eligibility of Katy Gallagher as a Senator disposed of five members of Parliament.
'Not only was Gallagher disqualified, but the consequence was that Susan Lamb, Justine Keay, Josh Wilson and Rebekha Sharkie had no legal ground left to stand on. They had to resign, and they did.
'In each case, although they had initiated the procedure to renounce their foreign citizenship before the nomination date at the last election, that procedure had not been completed in the United Kingdom and they were still formally British citizens on nomination day. That was enough to see them disqualified.
'... Realistically, the only way of removing this problem is by way of a constitutional amendment approved by a referendum. There have been many past proposals to repeal this disqualification, or to replace it with a requirement that all candidates be Australian citizens, or instead to give parliament the power to deal with the issue by legislation.'