The criticisms of Trump are unfair with this one. Obama would've have has his hands tied too. Saudis are a very important ally and many of you are underestimating the importance of the saudi alliance.
Obama was hardly a paragon of virtue on this issue, but he did suspend arm sales to SA owing to their repeated murder of Yemeni civilians:
The Trump administration resumed those sales, which are now being used to justify continuing ties with them:
Seems like too many people are missing out on this important fact. There might not be a ton we can do to stop them but we can certainly stop actively encouraging them via weapon sales.
It was only certain types of arms Obama restricted, and even then Saudi Arabia was also supplied with intelligence, fuel and other utilities to support their drones and planes in support of the Yemeni "war" during the Obama administration. I know Trump doesn't give a damn in the face of being able to say he created jobs and brought in money, but I won't hold Obama in a higher regard here when the coalition started under his watch.