The barbarians who did it were allowed into the country. We certainly could have prevented their being here. We certainly can keep these people out. The government of the United States has made a choice to keep us at risk rather than protect us by doing what is required - keeping these people out of here.
As I have said, because the government WILL NOT secure the borders, they are FORCED to watch everyone like Big Brother.
Or at least make it a lot more dificult for them to get here!