What is the Sharia ruling on my joining a political party with the aim of transforming my country's economy into an Islamic system and making it a model for Islamic countries?

The ruling on joining a party or group depends on its methodology and activities. If it is hostile to Islam, then it is not permissible to join it, due due to the prohibition of cooperating in sin and aggression. However, if it is founded upon truth and works for the benefit of the Muslim nation and the implementation of Islam, then cooperating with it is obligatory, due to the command to cooperate in righteousness and piety, and due to the hadiths that encourage unity.