To date, there have been millions of Muslims from various sects that emigrated from the Middle East (and countries that are increasingly Islamic Africa and Continental Asians, not just Oriental) into the United States. The United States has chosen a Caliphate as opposed to an Imamate, and therefore needs to come up with or institute a judicial system to enforce their laws.
Beheadings in particular are being instituted level with very little organization, and extreme internal bias. To the point that the People of the United States do not take Islamic law seriously, let alone their death penalties. By being so disorganized about The Sunna, the already violent opposing sect in the Shia peoples is only leading the People to believe that Islam is only made up of violence. There is little or no education to describe the difference between a time of Jihad and a time of peace in the life associated with Islam.
Beheading in particular is common but still slightly taboo among the Muslim populace. As a result, any country that is in the same position as the United States, a transitional one, now needs to institute a judicial system for the large populace that will no doubt continue to institute Islamic Laws via physical violence on an individual level, while simultaneously educating the largely Christian population.