عنوان مقاله [English]
There was a common belief among comparative studies researchers that parliamentary systems work better than presidential ones but that belief disappears now. These systems don't have any substantive privilege and their harmony with societies conditions make them better or worst. By using comparative methods we can find out this harmony and suitable form of government for specific state. Governmental instability in France third and fourth republic and Iran parliamentary monarchy show that because of lacking political culture to make durable coalition, parliamentary system isn't favorable to these countries. In both cases cabinets lasted about six mount an average that means instability leading to inefficiency of political system. That condition still exists in Iran appearing fundamental feature of the country that makes parliamentary system improper choice for governmental form in Iran political system, Apart from problem of instability, parliamentary system in Iran present government because of approbative oversee on election may lead to political alienation.