Woo! So far, we've had the following interpretations of the figure of
the `Whore of Babylon' in Rev 17 & 18:

a) The United States of America
b) MHO dB) which was as a figure of the fallen spiritual powers who
   corrupt and oppress human society
c) Historical Jerusalem
d) Historical Rome

Dare I suggest that the passage might be many layered in meaning? How
about * The prophecy reveals God's judgement on the corrupt & idolatrous
state oppressing his chosen people (d) * That God's judgement extends
_especially_ to his once chosen city (c) because, despite that City's
special call, it still rejected God's grace at the decisive time (Rev
11:8? - also isn't Rev19:24 equally suggestive of Rome as Jerusalem?) *
That the USofA is guilty of many of the crimes of Rome/Babylon (a) and
is equally subject to God's judgement * That the Good Book(TM) actually
encompasses _all_ these viewpoints by revealing the corrupting spiritual
powers warring against mankind through the very society that we've
created. (b)

Clever, huh? (<-- Flame here!) No need to argue at all! 

I think Mary's view has a lot of sense because there seems to be a
deliberate contrast between Rev 17/18 and Rev 21/22 - the mortal
Jerusalem chosen by God but never (historically) fulfilling its vocation
and the new Jerusalem perfected (outside of history) purely by God's
grace. eg Details like Rev 17:1 `.. who sits on many waters' cf Rev 22
the single stream in the new Jersualem `the river of life flowing from
the throne of God and of the Lamb.'