Houthis, Hadi and Yemen's political haze

Is the already fragmented Yemen heading towards chaos? President Abd-Rabbu Mansour Hadi resigned last week after Houthi fighters stormed his residence, following a dispute over the constitution. Political control in the capital remains uncertain for the time being. The situation is putting regional stability is at risk, as well as Yemen's relationship with the US, a key ally. What is needed to resolve this crisis?