If ______ city, USA disappeared tomorrow...

[xniNja]

I've been discussing the following topic with some friends and decided to get the input of the board.

Tomorrow, you wake up and turn on the television to find out that ____ city, USA, a reasonably populated and reasonably modern city has been completely blown off the map by a nuclear weapon.

The culprit is unknown, no one claims responsibility, but a website (whose origin is unknown or domestic) states that another city will disappear every week until the U.S. and its allies withdraw its hands from anything/everything (take your pick) in the rest of the world. Assume we can't figure out who has the nukes.

At what point would we be humbled? Could we be humbled? What would the current administration do? What would you do?