What happens if you are unable to draw because your library is empty?
They lose the game.

120.4. A player who attempts to draw a card from a library with no cards in it loses the game the next time a player would receive priority.
104.3c If a player is required to draw more cards than are left in his or her library, he or she draws the remaining cards, and then loses the game the next time a player would receive priority.
704.5b If a player attempted to draw a card from a library with no cards in it since the last time state-based actions were checked, he or she loses the game.