Allah the Almighty commands:
“Let there be among you a party who invite people to all that is good, require the doing of all that is right and prevent the doing of all that is wrong. It is they, who will find what they hope for.” (Family of Imran 3:104)
Preventing evil things does not necessarily mean forbidding them by force. One of the corresponding verses is as follows:
“Surely Allah commands to be fair, kind and generous to kith and kin; and He forbids all that is shameful, evil and oppressive. He exhorts you so that you may be mindful.” (The Bee 16:90)
The word translated as “forbid” is the same word that is translated as “prevent” in the previous verse. These are all stand for verbal prohibitions.
A country governed by the laws of the Creator cannot permit the Muslim community to produce/sell liquor or pork. But it can permit the Non-Muslim communities as long as they do not sell them to Muslims.
Gambling and Interest are things that should be forbidden. As a matter of fact, they are forbidden in the whole world. That’s why they can only be done by the special permissions of governments, in the permitted places and within the permitted boundaries.
Intercourse between unmarried couples should be prevented by blocking the ways for it together. This is one of the main problems that modern world is facing today. Too many communities are on the edge of losing generations. Problems of illegitimate children are being increased day by day. That’s why illicit intercourse should be prevented. Punishing however, needs either confession or 4 eye witnesses. This rule prevents arbitrary proceedings.
 See. 4:15, 24:2, 24:4.