Avoda Zara has Real power?

Avoda Zara (55a) Rav Yehuda said to Rava bar Rav Yitzḥak: Now, were I dead I would not have been able to tell you the explanation of this matter. It is therefore good that you reminded me of this matter while I am alive. The explanation is as Rav says: What is the meaning of that which is written: “And lest you lift up your eyes to the heavens, and when you see the sun and the moon and the stars, even all the host of heavens, you are drawn away and worship them, and serve them, which the Lord your God has allotted [ḥalak] to all the nations under the whole heaven”. The verse teaches that God allowed the nations to be misled by matters that seemingly indicate that idol worship is effective in order to expel the nations from the world due to their decision to engage in idol worship.

Ramban (Devarim 04:19) This means that every nation is assigned a star or mazal and above them is an angel. Because of this they made them into gods and worshipped them. In contrast Jews were not given a star because they are G-d’s portion and /He took them from the iron crucible of Egypt against the mazzel of Egypt.  

 Emes LiYakov (Devarim 04:19) And lest you lift up your eyes to the skies, and when you see the sun, and the moon, and the stars, all the host of the skies, should you be driven to worship them, and serve them, which the Lord your God has allotted to all nations under the whole sky Looking at the Torah commentaries you will see two approaches to explain this verse. One says it means that the sun and the moon were given to all people to provide them with illumination and the Torah is prohibiting worshipping them. In contrast the Ibn Ezra and Ramban explain it to mean that each nation has its own unique star and mazzel. Likewise there is a unique mazzel for every city which is the conduit for the good. This is also the view expressed by the Ramban in explaining Bereishis (01:18). It appears that this reflects a basic disagreement about the nature of idolatry. The view of Rambam  which is expressed in a number of places is that Idolatry has no real power to influence or do anything so those who worship idols or pray to them not only are sinning but they are wasting their time. In contrast the view of Ramban is that G-d created in Nature that each people has a unique celestial conduit to provide benefit to that people  as long as it is not relevant to Jews. since Jews are not influenced by mazzel. However there is still a Torah prohibition to pray to this source of bounty since ultimately G-d is the source of all bounty and therefore prayer and devotion can only be directed to G-d not to His servant. However if this source is worshipped and prayed to it can actually provide benefit. Thus the verse is saying that G-d gave each nation a unique source of bounty and guidance.

Emes LiYakov (Devarim 17:03) turning to the worship of other gods and bowing down to them, to the sun or the moon or any of the heavenly host, something I never commanded—  Rashi explains “I never commanded to worship them” And that is also how the Rashbam Ibn Ezra explain a previous verse concerning the verse.  And perhaps you will lift your eyes to the Heavens and you will see the sun and the Moon and the stars and all the Heavenly Host which G-d distributed to all the nations. The plain meaning of “which G-d distributed to all the nations.” is like what Rashi explains there that the Heavenly bodies were distributed to all the nations to provide light for them. However as I explained there that many Rishonim disagree with this and says it means that each nation has a special heavenly power. I explained that this dependent on the dispute of the Rishonim whether idolatry has any actual powerwhole sky.

Rabbeinu Bachya (Devarim (04:19) “not to raise your eyes skyward.”Seeing that certain such constellations appear to presage certain happenings at certain times, some people err in ascribing powers to these constellations. This is why the Torah warns the Jewish people not to raise their eyes to such parts of the sky and the constellations visible there. The “seeing” the Torah speaks of is not with the physical eye but with the mental eye, i.e. the conclusions derived from this “seeing.” 

Rabbeinu Bachya (Devarim 04:19) A Midrashic approach: the word “allocated” is connected to the word smooth, slippery. G’d flattered the nations with words in order to eventually drive them out of the world..

Rabbeinu Bachya (Devarim 04:19) We have a similar statement by the sages in Avodah Zarah 55: Rabba bar Yitzchak said to Rabbi Yuda: “there is an idol in our town, and whenever there is a drought with us it appears to a priest in a dream and says: ‘sacrifice a human being to me and you shall have rain.’ When the people of the town offer a human being as a sacrifice to this idol it really does begin to rain.” Rabbi Yuda commented: ‘if I had already died I would not have been able to explain the matter to you.’ Rav explained the words of the verse, to mean that G’d misled these idol-worshippers by letting them think that their idols had some power. By making them fall victim to that illusion He expedited their disappearance from this world.

Rashi (Devarim 04:19) WHICH THE LORD ASSIGNED to give light to them to all peoples. — Another explanation: which God assigned to them as deities; He did not prevent them from going astray after them, but He allowed them to err  through vain speculations, in order to drive them out from the world. Similarly it states, " God made him err through his eyes until his iniquity be found and he be hated”