Has Trump broken the 'rules-based international order'?

Commentators say that by withdrawing the US from international agreements, Trump has left a void in world leadership. But is he really to blame for the unravelling of the liberal international order? John Mearsheimer says that this is simply not true. Also, Malcolm Turnbull is said to have been responsible for the swing against the coalition in the 2016 election. He was the fourth prime minister in nine years. With the benefit of hindsight, what were the signs that he did not respect the Liberal tradition which meant he just had to go?