3- False beliefs, corrected : Muslims must not work under any political system other than the Caliphate

the allegation 

Muslims must not work under any political system other than the Caliphate .enjoined by Islam

:the Reply

Muslims are allowed to choose the system of ruling which fits their customs and traditions on condition that it must not contradict the Shariah of Allah. In this regard, it is of paramount importance to know that there is no single decisive text in Islam that obliges Muslim to establish a particular political system. They are rather ordered to maintain justice and run the affairs of people in a manner that pleases Allah, the Almighty.  
• All the regimes that followed the era of the Rightly Guided Caliphs cannot be called “caliphates” unless on a linguistic basis. In reality, they were different from each other in such a way that clearly indicates that regimes in Islam differ according to people’s customs, cultures, and circumstances.