What does Gene mean when he says "Phineas, you wouldnt be any good in the war, even if nothing has happend to your leg."

Phineas has never been one to not get along with people. He knows no other way except to be popular and to have people like him. Finny could not imagine a world in which people are hateful and hated, would hurt one another, or would cause someone else pain. The point is that no matter what, Finny would never have "what it takes" to fight in a war and do what needed to be done in a war-time situation.