CANBERRA—The left-leaning Labor party secured re-election in Australia’s least populous state on Sunday as voters backed the party for implementing some of the country’s most stringent restrictions to slow the spread of the coronavirus. Labor is predicted to claim up to 53 out of 59 lower house seats on the back of a stunning 13 per cent swing in Saturday’s election. “The magnitude of what happened today is not lost on me. With it comes great responsibility,” state Premier Mark McGowan told supporters in Perth, Western Australia’s capital. The election was seen a referendum on McGowan’s hardline handling of the COVID-19 pandemic. Deputy Premier Roger Cook said voters had rejected the Liberals’ campaign against handing Labor too much control. Retiring former Liberal leader Mike Nahan told the ABC that he believes a call by the Liberals to open WA borders while the state continued to deal with COVID-19 had done …