Poseidon is skeptical that Hera hopes to gain control over all of Olympus. If it is true, he will make her kneel to him. The world was split between the three brothers - sea, heavens, and hell. The rest were scraps left to the other gods. Now, he has the power to destroy those scraps or leave them be. It will be up to the others to decide which they want. Without a king, he says, Hera has nothing.