Where'd I put that PHB... It reads:
Lawful Good: A Lawful Good character acts as a good person is expected or required to act...She tells the truth, keeps her word, helps those in need, and speaks out against injustice.
Chaotic Good: A chaotic good character acts as his conscience directs him with little regard for what others expect of him.
Lawful Neutral: A lawful neutral character acts as law, tradition, or a personal code directs her...She may believe in personal order and live by a code or standard, or she may believe in order for all and favor a strong, organized government.
Chaotic Neutral: A chaotic neutral character follows his whims. He is an individualist first and last. He values his own liberty but doesn't strive to protect others' freedom.
Lawful Evil: A lawful evil villain methodically takes what he wants within the limits of his code of conduct without regard for whom it hurts. He cares about tradition, loyalty, and order but not about freedom, dignity, or life.
After all, needing to obey tyrants would royally screw Paladins over.

I'm pretty sure a "The ends justify the means" mentality isn't necessarily chaotic, but might not be good either way.