The nations of the world that were once blinded before the cross have now have been opened up to the light and truth of the Gospel - and there is nothing Satan can do to stop it. Satan (the accuser) has been soundly defeated by Christ. His firing pin has been taken away. He has been shackled in regard to his previous widespread spiritual power over the Gentiles. He is now powerless and impotent to stop the people of God advancing the Gospel commission in the will of God. His power over the saints has been demolished through the blood of Christ. That is why he has no more access to heaven and no power to accuse the elect.It says that he will not be able to deceive the nations. Everything you just said about what Satan is NOT able to do, he is currently doing.
Edit to add: John specifies the content of his deception later in the chapter.
Revelation 20:7-10 When the thousand years are completed, Satan will be released from his prison, and will come out to deceive the nations which are in the four corners of the earth, Gog and Magog, to gather them together for the war; the number of them is like the sand of the seashore. And they came up on the broad plain of the earth and surrounded the camp of the saints and the beloved city, and fire came down from heaven and devoured them. And the devil who deceived them was thrown into the lake of fire and brimstone, where the beast and the false prophet are also; and they will be tormented day and night forever and ever.
John's point is to say that for a thousand years, Israel will be able to live in peace without fear of being attacked by her enemies. Even when Satan is released, his armies will be destroyed by fire.
Israel is not living without fear from her enemies. Therefore Satan is not bound and the Millennium hasn't begun yet.
Whilst Satan still carries the power to deceive individuals, he has lost the ability to keep the Gentiles (ethnos) as a collective whole blinded. Scripture after Scripture in the New Testament proves that.
It is His aim to hide what was secured at the cross in case believers and unbelievers will get fully liberated and do damage to the kingdom of darkness.
- He is already judged – his fate is sealed.
- False accuser cast down.
- No more access to heaven.
- Knows his time is short.
- Doesn’t have anything on us anymore. Past, present, and future sin has been paid for.
- The militant Church is a resistance movement against Satan and his lies as they spread the light of the glorious Gospel of Christ.
- Satan’s playing field - the Gentile nations - is enlightened.
- The Gentiles are now without excuse.
- Believers now overcome Satan by the power of the blood of Jesus made personal in their life.