Okay, but my question was/is "Why do you think Rev. 8:8-9 refers to the USA in association with Satan standing on the shore of the sea and a beast coming out of the sea?"
Okay, very good.
The Book of Revelation is set to four storylines.
The first is the seals from Chapter Five through Chapter Seven
The second is the trumpets from Chapter Eight through Chapter Eleven
The third is the mark of the beast from Chapter Twelve through Chapter Sixteen
And the fourth is the fall of Babylon in Chapter Seventeen through Chapter Twenty-Two
The idea is to find the corresponding subject matter in all four storylines. And so when looking at Rev. 8:8-9 it is in the fall of Babylon judgment from Verses 8:7-12. That is, there are five total judgments the first of which is the judgment upon Babylon. The fall of the US is in the judgment upon Babylon.
The fall of Babylon in the seals storyline is Rev. 6:3-4
The fall of Babylon in the trumpets storyline is Rev. 8:7-12
The fall of Babylon in the mark of the beast storyline is Chapter Thirteen
And the fall of Babylon in the the fall of Babylon storyline is Chapters Seventeen and Eighteen
The analysis:
The rise of the beast (Rev. 13:1), who is a servant of Lucifer, corresponds with the judgement upon Babylon (Rev. 17:1) where John sees the whore Babylon upon the 13:1 beast (Rev. 17:3). The judgment is: that the 13:1 beast will remove Babylon from off his back thereby destroying Babylon.
This is done by overtaking the seventh Babylonian economic system referenced in Rev. 17:10. This seventh system is also referenced in Rev. 13:2 and is the subject of Dan. 7.
But before the 13:1 beast can overthrow the seventh economic system he must first bring down the sixth economic system and this is done using the ten kings stated in Rev. 17:12. These ten kings devour the sixth economic system, whose judgment is being addressed in Chapter Seventeen.
Thus, the burning of Babylon in Rev. 17:16 is the destruction of the mountain in Rev. 8:8-9. Mountain is metaphor for nation/kingdom. By destroying the mountain (Rev. 8:8-9) then Babylon the economic system falls (Rev. 18:2).