After assassination of Jamal Khashoggi, a Washington post columnist and journalist, who were writing against Mohammad Bin Salman for years, the political map of the world and middle east changed a lot:

Trump tried to isolate MBS, the crown king, from the case, but failed and CIA, Congress, House and the public opinion saw MBS involved in the assassination. Trump became a bit conservative about the case, I believe hoping the hype fades away and nothing happening to their arm deals.

Turkey tried to push US hard to force them for Gulen return to Ankara. Erdogan used all the cards he had. and many believe they were aware of Saudi plan and could stop it, as MI6 and FBI previously did. otherwise Khashoggi was killed before!

Russia...
Putin were no where in the dialogue among nations and watched the process carefully. and now, here is Putin's decision:

Russia Warns U.S. Against Interfering in Saudi Royal Succession

this is Bloomberg's title, saying Putin backs MBS completely.

This is a moment of making a decision for Russia. a point of no return I believe. Putin has made a big mistake, if the world's leaders do not welcome Saudi prince in the end and MBS never becomes the king.

OR

for any internal reason, MBS or Saudis totally lose the control over a country which holds a family name and reserves the largest oil resources in the world.

which is not unlikely in a region which governments are very often unstable and changing by the way...

OR

Putin has made a critical pivot to make its position in world's oil and energy game, stronger, more stable and more powerful.

I am very sure that Trump would loved to take same position from the very beginning, but the difference between Trump and Putin is, one's nation and political system doesn't let the president do whatever policies take, and the other is completely ruined by dictatorship of a man, silenced all the oppositions in last two decades.

the original article in Bloomberg and the image's source:
https://www.bloomberg.com/news/articles/2018-12-26/russia-warns-u-s-against-interfering-in-saudi-royal-succession