Negotiating Membership in the WTO and EU

With the accession of Afghanistan in 2016, the World Trade Organization (WTO) numbered 164 members with nineteen other states in line to join. The WTO is certainly not alone in its growth though; the Organization for Economic Cooperation and Development (OECD), the North Atlantic Treaty Organization (NATO), and the European Union (EU) are all expanding with dozens of states continuing to negotiate their potential membership. What impact does membership in international organizations really have?