Why did king leonidas disobey the councils vote in the movie 300?

Leonidas' decision to disobey the Council and march forward to the Hot Gates and vanquish the Persian army was founded in his determination not to surrender Sparta to Xerxes. When he presented his battle plan to the council and was given no as an answer. Despite his anger he doesn't want to disobey the Ephors, his wife persuades him to rethink his strategy and take 300 soldiers as his personal guard to battle along with the Greeks at the Hot Gates and reduce the Persian's army military capacity.