World-System or World-Empire?

Friends

     If we can step away from the Ad Hominem attacks for a moment
(which violate WSN rules anyway), there is a serious substantive
issue bobbing & weaving throughout the exchanges on Hardt,
Marxism, and World-System theory which I believe merits serious
consideration:  is the world-system evolving into a world-empire? 
If so, is this transition due to a sufficient difference in
QUANTITY (international exchanges) becoming a difference in
QUALITY (emergence of a global state)?  Conversely, if not, is
our perception that it could be such a transition due to our
focussing too much on the changes and not enough on the
continuities?

     My own view is that we ARE morphing into global empire, and
that such a process has been underway since Capitalism first
appeared. Although the stability of the world-economic structure
WITHIN the capitalist realm since c. 1400 may give us the
illusion of long-term stability, one serious glance at history
illustrates that the periods between successive empires have
lasted up to 1,000 years, and that, for example, the "warring
states" period of Egyptian history between the Old and New
kingdoms was of similar length to the life-span of capitalism to
date.
     If this were to be true, then one corollary question is
whether such a global state could remain capitalist for long, or
whether the long-term demands of state legitimacy would require a
fundamental lessening of unequal exchange and even a possible
reversion to a tributary state.

Cheers,
Peter