Everyone (well, most people) always say that Ned Stark's sense of honor was what brought him down, what made him go to Cersei and warn her what he had learned. It gets said all over the internet, in magazines and newspapers, literally everywhere that talks about either the books or the television show.

I agree that Ned Stark does have a strong sense of honor, a code he is determined to live by though it may even cost him his life.

But that isn't what killed him.

I believe that more than honor, the protection of children (any children) was Stark's utmost objective.

Think about it.

(Quick note: I assume the L+R=J theory to be fact)

Ned soils his honor to protect the infant child of his sister, impugning his own honor and causing a childhoods worth of grief for the boy at the hands of Cat. He lies to his best friend and king, his wife, and the entire realm to protect this child from Robert's vengeful wrath.

Ned defies Robert and the Small Council, and steps down as Hand all over them wanting to kill Dany, who he refers to as just a child.

Ned warns Cersei, a woman he knows is a traitor (her infidelity to Robert is treasonous) and has cheated on his best friend, that he knows her secret. Why? As he says, to protect the "innocent" children.

Ned lies and confesses to treason himself, and declares that Joffrey is the only true and legitimate heir to Robert, all to protect his two girls, both still children.

Am I wrong?