A South Korean presidential front runner on Thursday said his country should reconsider plans to deploy an advanced US missile defence system to cope with North Korean threats, a move Washington will likely to see as disruptive. Liberal opposition politician Moon Jae-in said the security benefits of having Terminal High-Altitude Area Defence (THAAD), would be curtailed by worsened relations with neighbours China and Russia. He downplayed concerns that backtracking on the plans would cause tension with the US, which he said was the “most important country” for South Korea in face of the nuclear-armed North. The issue of whether or not to deploy THAAD should be pushed to the next government Moon Jae-in, presidential contender “The issue of whether or not to deploy THAAD should be pushed to the next government,” Moon said. “Reconsidering THAAD would have to be preceded with diplomatic efforts, including diplomatic efforts with the US. I don’t think that the reconsidering of THAAD would harm the South Korea-US alliance.” Recent opinion polls have shown Moon as a presidential favourite amid the popular anger over conservative President Park Geun-hye, whose powers were suspended after lawmakers last week voted to impeach her over an explosive corruption scandal. South Korea’s Constitutional Court has up to six months to decide whether Park should permanently step down. If Park is formally removed from office, the country would hold a presidential election within 60 days. Moon, who conceded the 2012 presidential race to Park, said he expected the court to rule on Park’s impeachment some time between late January and early March, setting up a presidential election around April or May. “It would be a huge honour for me if I can take part in the next presidential election,” Moon said. South Korean military officials in September picked a private golf course in the country’s southeast as the site for THAAD, which was slated to be deployed by the end of next year. They originally chose a nearby artillery base in the rural farming town of Seongju as the site for the system, but changed locations following fierce protests from locals who expressed concern over potential health hazards they believe the system’s powerful radar might cause. Park Geun-hye’s impeachment raises new level of uncertainty on Korean peninsula The plan to deploy THAAD in South Korea has angered not only North Korea but also China, which suspects the system would allow US radar to track its missiles. Russia also opposes deployment. Moon also argued that Seoul should put dialogue over sanctions in persuading Pyongyang to give up its nuclear ambitions. He rated the Park government’s hardline stance against North Korea as a “complete failure” because it “didn’t function in any way” to prevent the North from expanding its nuclear weapons and missile programmes.