Proplog2
While there may be several indications that Babylon The Great referred to in the book of Revelations might after all be the United States, however, there are other issues that need to be considered.
Blood of holy ones is said to have been found in Babylon, indicating that at some point this entity will persecute true Christians. The US at present is not persecuting Christians, although one could argue that the US is protecting organized religeon in the US and abroad, which in turn IS persecuting true Christians. However, things could change to the worse. The US demographics are changing toward a plural multi-ethinic society that tend to favor more liberal values and less conservative ones. The current US administration makeup of so called Christian right individuals and the adoption of conservative policies might one day backfire and create a backlash against those policies and the entire Christian right culture.
Babylon the Great is said to have fallen and God is seen telling "his people" to flee Babylon before it is destroyed. You seem to indicate that JWs are alone considerd to be "God's People". I do not share this view. God's people are those that are truly following Christ and not some man-made organization.
One indication that would confirm the identity of Babylon The Great as the United States, is if one day we begin to see an exodus of some Christians from all denominations starting to take place. Remember that an angel in heaven is said to be proclaiming the downfall of Babylon and telling God's people to get out. This would indicate that at some point in time, true Christians would suddenly get an urge to flee.
A nuclear attack on Manhattan, while may not be far fetched as you seem to allude, would incinerate many nominal as well true Christians before they get a chance to leave.