again and again...
Sharia law can only be imposed on Muslims in Muslim lands.
In a land that is ruled and dominated by Christians or Jews or Zorastrians or new agers can not be forced to abide by Sharia law.
In a land dominated by Muslims, christians and jews are free to practice their religion. This is evident throughout history with the existance of the Coptic Christians in egypt, with Greek orthodox church in Turkey, with safardic Jews in North Africa, with Etheopian jews and christians in Kenya, Etheopia, and Somalia.
The reason why many of these churches still exist is directly because the Muslims aloud christians to freely practice unimpeded, while in christian dominated areas, these churches were considered hereticle and wiped out by the catholics.
The majority of Shari law applies only to Muslims, if a christian commits adultery, he is handed over to christians to impose whatever punishment they feel is necessary. There are some rules christians have to abide by, one of which is paying the jizya tax, a tax imposed on non-beleivers to pay for protection by the army from foreign invaders, and also to pay for upkeep on churches and synagogues (as was done under the ottomans).
If adhereance to sharia law is terrorist behavoir, then every Muslim will be considered a terrorist, because every Muslim is obliged to follow sharia law. If this is the route you want to take, your going have to outlaw Islam as a whole and go against your own principals.