But they acknowledged that internal upheavals accounted for far more of the problems.
And the United States itself would be torn apart by the worst internal upheavals in a century.
"Lots of reasons: a shipment got lost, an internal upheaval."
I can't think of a single thing that involves more internal upheaval than the adolescent years.
Researchers continue to speculate whether the Olmecs' decline can be attributed to internal upheaval or invasion by outsiders.
These internal situations should be respected if we wish to avoid internal social upheavals.
Sudan has a long history of violent internal upheaval and recent developments indicate a return to this past.
The French authorities were too busy with internal upheaval to pay the incident much notice.
Completing the revolution will require rather more internal upheaval than Novak is willing to sanction.
The group has seen a number of upheavals both internal and external during its history.