What are the duties of a citizen toward his country? A citizen must love his country, be sincerely interested in its welfare, and respect and obey its lawful authority.
How does a citizen show a sincere interest in his country's welfare? A citizen shows a sincere interest in his country's welfare by voting honestly and without selfish motives, by paying just taxes, and by defending his country's rights when necessary.
Further reading: CCC 2238-2243