PHOTO: President Obama with Vietnamese counterpart Tran Dai Quang on Monday

What exactly is Barack Obama doing in Vietnam this week?

Well, there’s the symbolic dimension of shaking hands, more than 40 years after America’s defeat by the North Vietnamese. There’s the economic lure of the Trans-Pacific Partnership, as well as direct trade that has increased 100-fold in 20 years.

And then there’s the message to China, as the US lifts its embargo and starts supplying arms to the Vietnamese.

I chatted about all the dimensions with BBC Radio Wales on Tuesday morning.

Listen to interview