Its spiritual warfare. If you bind or bar the spirits of darkness from operating in America those they impel will lose their impetus. Its that simple. They keep motivating you to use physical means because the Adversaries lack adequate spiritual means to defend against the sons and daughters of God. If you look back in history you'll see remarks of how after the resurrection the oracles and spells in Rome stopped working. The key reason they want rid of true believers is because true believers trump their spellwork. Look at the rank/level explained at Ephesians 1 & 2. The witches and warlock CANNOT do anything of a higher order than a true believer. To reiterate, they are aware of the power and rank differentials thusly getting people to rely on less than adequate means requires use of mental/emotional methods. If you have the best and most powerful weapon at your disposal, an intelligent adversary might try to use means to get you to fall back to something less adequate.
Keep in mind that both DHS and the Government of the United States are subordinate to someone, something...somehow.
Related: Egregores