"This is why we say the progress continues to be fragile and reversible and it is why we say it requires continued vigilance and continued effort, " he said.

CNN: Petraeus: Afghanistan could be harder than Iraq

As General Petraeus himself admits, and our briefing this week argues, the change is fragile, and reversible (see article).

ECONOMIST: Iraq

While Gen Petraeus backed the proposed drawdown, he warned that progress in Iraq remained "fragile" and "reversible".

BBC: Profile: David Petraeus