We do not need a constitutional amendment to elect the next President by national popular vote. The National Popular Vote Interstate Compact is an agreement among the states that they will cast their electoral votes for the candidate who receives the most votes nationwide – not just in their state. Once states with the combined 270 electoral votes needed to win the Electoral College join the Compact, those states will vote for the winner of the national popular vote. It does not matter whether some states do not agree. If states with 270 electoral votes agree that they will vote for the winner of the national popular vote, the candidate with the most votes across the entire nation will become President.