In Daniel chapter 10, an angel of the Lord appears before Daniel because "..you set your mind to understand and humbled yourself before your God, your words have been heard , and I have come because of your words." We see here that the Lord sent an angel, a messenger, to Daniel because he had set his mind on the Lord to understand.
The angel goes onto say "The prince of the kingdom of Persia withstood me for twenty-one days; but Michael, one of the chief princes, came to help me, so I left him there with the prince of Persia..". This was spoken while Daniel along with the Hebrews were held in captivity in Persia or present day Iran.
From this passage we see that Satan, the prince of the world, sets his demons as guardians over countries and principalities to keep God's message or messengers from the people. This guardianship is not limited to other parts of the world - it is present even in America.
As seen in Matthew 4:10 Satan tempted Jesus by offering the kingdoms of the world to Jesus if he would bow down before Satan. Jesus did not refute Satan's claim to own the world, he told him only to begone. If Satan does indeed own the world, then we can be sure there is a Prince of America who stands guard to keep God's message or messengers from the people.
To keep the message and messengers flowing, we must be vigilant in what Daniel did. We must pray continuously and set our hearts to understand the Lord.