As the Middle East undergoes a once-in-a-generation shift in political fault lines, great power diplomacy could make the difference for millions between peace and stability or turbulence and endless conflict. So what's driving that diplomacy? Between the US and Saudi Arabia, it's a confusing mix of bilateral security ties, regional reach-outs to the likes of Syria and Israel and personal enrichment. We ask about the Trump family's longstanding ties to the kingdom, as well as reports that the US president is about to get a lot richer.