Mom and Dad Disagree About Child Discipline

How can my wife and I come to an agreement about child discipline? I've tried to teach my son a strong sense of discipline, but my wife often disagrees with my approach and methods. She says I'm "too hard on the boy." As you can imagine, this can sometimes become a sore spot in our marriage. How can I fulfill what I believe to be my obligations as a father while still honoring my wife and respecting her perspective?