Just confirmed. 
As I suspected, this is what they meant, but they clarified: *strong as in conomically prosperous.*

I think the person posing the question meant 

whatever is conventionally meant by strong in the sense that it is expedient to the nation's prosperity

AskSN

What makes a country strong?

billytheked

Good point. 
I think the person posing the question meant *whatever is conventionally meant by strong in the sense that it is expedient to the nation's prosperity*, but I'm not sure I'll have to ask. 
