The average intelligence of Jews is higher than that of any other ethno-religious group.
There could be many reasons.
Israelites were probably the first people who had a written scripture - If you read the Quran, you will notice that no book is mentioned before the times of Moses (PBUH).
It is also argued by some historians that it was Israelites - not the Phoenicians - who invented alphabets (alpha = aleph = bull; Bet = Bait = Home).
So, they had an early encounter with the written word, which was also deemed sacred. That ensured keeping literacy levels high as a must in Jewish populations through the ages. The tradition of learning in Israelites is as old as the beginning of Mosaic law.
When a population goes through a bottleneck, let's say a war, mostly the 'brawn' are sent to fight and the 'brains' is left at home and has higher chances to procreate. This could have contributed to the increase of average intelligence in the Jewish Gene Pool.
Throughout the history, Jews have been one of the most persecuted people - they were mistreated by almost every imperialistic power - save the Muslim empires where they thrived; in fact Maimonides, considered the greatest Jewish Scholar in last 2000 years was born and lived in Muslim lands. During the times of hardship, the survival of those people is increased who possess an advantage to live through the harsh times.
During the Medieval times when Jews were persecuted throughout Europe, they had an essential survival tool to live through these hard times - they became the moneylenders. Usury was not allowed in Christian Faith, but Jews were allowed to deal in transactions involving usury - this way they became a 'necessary evil'.
Although, this earned them the right to survive in Christian lands, life was hard and a person had to be multi-talented, stubborn, hard-nosed, shrewed and hard working to live through the times. Add to that the strict intermarriage customs in Jewish populations. Certain traits grew at the expense of others. Consequently, the today's Jews - especially the descendants of European diaspora - have the highest intelligence coupled to highest incidence of certain genetic diseases in the world. It's a mixed blessing.
As to why the Jews are so powerful, the most important factor is the religious indoctrination which tells Jews that they are 'God's chosen people' and one day the people of the World will serve the Israelites; "With their faces on the ground they shall bow down to you, and lick the dust of your feet. Then you will know that I am the Lord". To Jews, this gives an unlimited 'holy licence' to exploit the gentiles to fulfill the 'Yahweh's Promise'. (Here I also remember Jonas Salk who declined to patent polio vaccine because royalties and profits would raise the cost).
They were/are united for a cause.
