i wouldnt be so hard on her.. she had extensive knowledge of the political debate in australia as it is something we are exposed to on a daily basis. it was easy to challenge julia and tony - as there is a ready history of their positions/quotes etc. the guy they had on last night may not have been such a well known personality and his positions were not that clear. there wasnt time to prepare for the interview due to the sudden turn of events.
notice how she posed a question about his position on something and he immediately denied it. she looked baffled and didnt have a rejoinder as she had nothing to fall back upon. if it was tony/julia, she would have recalled anything they might have said to the contrary earlier... but this guy was an unknown quantity.
the interview required more research and she was put in an awkward position to conduct it.
