What impact did the war of 1812 have on american nationalism (national identity)? question 2 options: the war reduced nationalism because it was a decisive defeat for america. although the war was a decisive victory, it had no impact on american nationalism. although the conflict was indecisive, it boosted american nationalism because the american army and navy proved they could stand up to the most powerful country in europe. although the war was a decisive defeat, it had no impact on american nationalism.