The easy way out, for the US at least, is to "let China do it." President Donald Trump, Secretary of State Rex Tillerson, Defense Secretary James Mattis and UN Ambassador Nikki Haley have in unison chanted the same basic mantra: The problem would be solved if China would apply more pressure on North Korea.
First there is no evidence China can tell North Korea what to do with any real hope of success. The two countries are not buddies and there is no love lost between China's President Xi Jinping and North Korean leader Kim Jong-un. They have not met since both leaders came to power in 2012 and they communicate via messengers.
China has supported a UN resolution strongly condemning North Korea. The Kim regime no more pays heed to China than it has to protests from South Korea, Japan or the United States.