National Security Adviser Wi Sung-lac said Friday that any renewed dialogue between the United States and North Korea must produce substantive progress on Pyongyang’s nuclear issue. Wi also stressed the need to prevent South Korea from being sidelined in the process, emphasizing the importance of close coordination between Seoul and Washington toward that goal. His comments followed concerns that the U.S. may set North Korea's denuclearization issue aside to restart talks with Pyongyang and that U.S. President Donald Trump's renewed push for a summit with North Korean leader Kim Jong-un may sideline the South. “As a key party to peace on the Korean Peninsula and a pacemaker, we will support efforts to build trust between North Korea and the U.S. and resume dialogue so that President Donald Trump’s efforts can lead to renewed talks,” Wi said during a press briefing at Cheong Wa Dae. He noted Seoul would coordinate with the U.S. so that any potential Washington-Pyongyang dialogue leads to “substantive progress on the North Korean nuclear issue, along with the establishment of a p