ws Khilafa is relatively easy...we think we have to destroy the current system and replace it in any particular land. We do not. All nation-states allow non state organizations to form within the state (clubs, associations, corporations etc.) We (Muslims) could create a small association or organization which gradually grows. Every city in which Muslims live could appoint a leader who applies the shariah who then collects Zakaat has a baitul mal etc. Building a government within the shell of the existent one.