Updated

An independent Australian senator who is British by descent has become the eighth lawmaker to leave Parliament in recent months over a 116-year-old constitutional ban on dual nationals running for office that threatens to bring down the government.

Jacqui Lambie tearfully resigned Tuesday, a day after the Senate set a Dec. 1 deadline for Australia-born senators to provide documented evidence that they had not inherited the citizenship of an immigrant parent or grandparent.

The conservative coalition could lose two seats in by-elections next month after lawmaker John Alexander resigned from Parliament last week because he was likely British.

Kristina Keneally, a Las Vegas-born former New South Wales state premier, has announced she will run for Alexander's seat, having renounced her U.S. citizenship.