I agree the full sentence would help. Lacking that,
"a strong powerful country, who will fight for their rights." is not a dependent clause; it is a noun phrase (a strong powerful country) which is modified by a relative clause (who will fight for their rights) (thank you StoneyB). Still, it does not express a complete thought.
Therefore, it should not follow a semi colon, for semicolons join two independent clauses (when they're not separating items in a list that already involve commas.)
It would be a wrong use of a semi colon here:
I love Liechtenstein; a strong powerful country, who will fight for their rights.
correct (grammatically):
I love Liechtenstein; it is a strong powerful country, who(which?) will fight for their rights.
source: https://owl.english.purdue.edu/engagement/2/1/44/