In such matters about which there is no clear command or instruction in the Qur'an and Sunnah, the problem is decided keeping in view similar and resembling cases. This mode of deciding about its being permitted or prohibited is called Ijtihad.
Evidently, this process can be employed by only such a person who has full command about the various branches of knowledge pertaining to Qur'an and Sunnah. Not every person can do it nor is supposed to do it. There is also a famous proverb that says: `Little knowledge is a dangerous thing.'
From here we conclude that the ruler, judge or a bureaucrat in a Muslim country should be a learned scholar, i.e., an `Alim well versed in Qur'an and Sunnah; so that he can interpret the laws of Islam with utmost care and in a befitting and sincere manner. He should do the job sincerely and with a pious intention. With such mode of work, he will be bestowed with reward in every case. However, if his interpretation is correct, he will receive a double reward.