You must note that the war was started by Sparta, and that Sparta had a better army, while Athens had a better navy. Since Sparta initiated the war, they were usually able to choose whether the battles would mostly be on land or in the sea. Sparta acted on them having a better land force, and invaded through land, which led to Sparta's victory.
Selective incorporation is a constitutional doctrine that ensures states cannot enact laws that can take away the constitutional rights of U.S. citizens that are included in the Bill of Rights.
