Ahn, there's nothing grammatically incorrect, but I would not have had to work as hard to understand if you had started with "If" instead of "Had," and used "era" instead of "age." Also, perhaps "shows" could be "holds"?
EU residents, do you not use "the"?
If an era where (or "in which") economic strength holds more power than military force (had) arrived, the(?) EU could have ex