A new chapter in Pacific security began this week as Australia and Papua New Guinea signed a mutual defence agreement that draws the strategically vital yet volatile Melanesian nation further into Canberra’s sphere of influence – as China watches closely.The “Pukpuk Treaty”, signed in Canberra on Monday by Australian Prime Minister Anthony Albanese and his Papua New Guinean counterpart James Marape, is Australia’s largest Pacific security pact in seven decades.Named after the Tok Pisin word...