Us versus them: Concern as polarised politics turns increasingly violent in US

The shootings of two politicians and their partners in the US state of Minnesota has sent shockwaves through the state - and the country, with many states taking precautions to protect their representatives from harm. But analysts say the shootings are the latest in a long line of politically motivated attacks and acts of violence, mostly from right-wing extremists. Deborah Groarke takes a look at this troubled history - and asks, what about Australia?