Adelaide city councillor Henry Davis** is challenging firebrand conservative senator Alex Antic for Simon Birmingham’s Senate spot. Antic wants to install current state party president, Leah Blyth, in the casual vacancy created by Birmingham’s resignation last week. Blyth is the most likely replacement according to Liberals, despite Davis's challenge. Davis had a big week appearing in court for a defamation case and parodying the Adelaide lord mayor. Meanwhile, Trish Worth warns that the party’s hard right, led by Antic, has changed the makeup of the council. Davis says Antic controls the state branches and councils, making it hard for a moderate to take over from Birmingham.