Donald Trump on way to meet Kim Jong Un in Vietnam

US President Donald Trump is on his way to Vietnam to meet the North Korean leader Kim Jong Un for a second summit. Mr Jong Un is travelling to Hanoi by rail from Pyongyang. Mr Trump tweeted that with complete denuclearization, North Korea would rapidly become an economic powerhouse, and without it it would be more of the same. Our correspondent in Washington, Giles Gibson, speaks to Susie Ferguson.