In its ambition to be world ruler the US always has had its share of misbehaving friends. Mobutu was probably the most famous among them, but there have been many others. Out of fear of losing their support the West tended to ignore their misbehavior.
Nowadays Israel and Saudi Arabia are among the misbehaving friends. And we see the US bending backwards in order not to lose their friendship.
Doing so the US is showing itself a false friend. Good friends occasionally tell each other the truth. Forcing Israel to behave better towards the Palestinians could in the long run be better for Israel's future.
In the case of Saudi Arabia this issue is even more clear. By starting a war against Yemen the royal family has painted itself into a corner. The main initiator of the war is crown prince Muhammad, king Salman favorite nephew. Stopping the war would be a major defeat for Muhammad. This is by excellence an opportunity for the US to show itself a true friend: by stopping all support for the war and starting humanitarian support for Yemen it could force Saudi Arabia to end its war. On the short term the Saudi's certainly would blame Obama - also in an effort to save Muhammad's face. But in the long term they would have to admit that it was the best option.
Yet this kind of behavior takes courage. And until now that has been missing.