WI the State of Israel chose to become a crowned constitutional republic, with a hereditary post like "Lord Protector" or "Stadtholder" or whatever you like as head of state (call it anything but king), which would have the same position as the President of Israel in OTL? They select the House of Rothschild to fill this post and be the ruling dynasty, the most preferable candidates would be the prominent Zionists in the family, Edmond James de Rothschild from the French branch of the family and Baron Walter Rothschild from the British branch. But by 1948, they are both dead so maybe Edmond's son James Armand de Rothschild, who donated the Knesset building, could reign as the first "Stadtholder of Israel".