"Round them up" is what we did in northern Ireland, it didn't work and we helped recruiting for the IRA. Lots of argument on here about religion being the cause or not. Also politics, oil? The one common aspect in so many confrontations throughout history has been that an element of society has felt disadvantaged in some way and a proportion of those have taken to violence to fight back. The sides in these arguments have had many different identifiers, Religion, political, power, food etc. On a much less relevant level you can include football. Disadvantage between clubs drives rivalry and we have even seen bits of that on this thread. Common sense needs to prevail through the fear. We did not lock up or throw out all English Catholics in the 70s and we need to show the same common sense now.