In view of the fact that the unbelieving Jews are never referred to as being “saints” in the book of Revelation (e.g., Rev 16:6; 17:6; 18:20, 24), it seems more appropriate to see this war as the Neronic persecution upon the Church (the real “saints”).
Jesus called the Jews “sons of your father the Devil” and “brood of vipers.” Satan used the Jews to deceive Nero into blaming the fire of Rome upon the Christians, and Nero implemented that suggestion immediately. This very effectively launched the final war upon the Church (AD 64-66). When that “great tribulation” had pretty well run its course and eliminated most of the “saints”, Christ came in judgment upon the Jews. That war (the great tribulation) was cut short (Matt. 24:22) when the Jews rebelled against the Romans and subsequently the Romans now turned their energy and focus upon the Jews.
If you look in some of the various Preterist commentaries of Rev. 20:9, you will notice that they apply this to the Zealot armies and their international confederates who persecuted Christians and attempted to destroy the church. Their tribulation against the church was turned back upon themselves. God used the Roman armies to destroy those who attacked His true spiritual “camp of the saints” and “beloved city” (the Church). It is not talking about the literal physical city of Jerusalem, but the spiritual heavenly city (the Church). After AD 30 and the crucifixion of Jesus, the physical city of Jerusalem was no longer the “beloved” city of God. The Church was His new “beloved” bride. Anyone who threatened the Church would be destroyed, but the physical city of Jerusalem was left unprotected.
This verse warrants saying that it is a different city (the heavenly city) that is being attacked here by the beast. Notice how Rev. 19:19 flatly states that this “war” is against “Him who sat on the horse and against His army.” That army of Christ is His angelic hosts and saints (cf. Rev. 19:14). The Zealots attempted to destroy the Church (persecution & tribulation), but Christ brings destruction on the Zealots instead. Again, there are TWO different cities being discussed here in Revelation 17-22. There is no reason to confuse them. Keep them separate. The earthly Jerusalem is identified as the “harlot” and the “Great City,” while the heavenly Jerusalem is identified as the “camp of the saints” and the “beloved city.” You need to notice that distinction and watch for it throughout this whole context of Rev. 17-22.
[For a more in-depth study see eschatology “Study Series 16 Lesson 7 Rev. Chapters 19 and 20 (sub study on The Wedding)”]