These were called the Palmer raids and were a part of the red scare. He did it because they were accused of being communists and anarchists, or were just too much left and liberal. This was out of fear that they might get enough people and start their own revolution in the country.
Media saturation is the constant bombardment of media whether it be tv, magazines, radio, ads etc definition saturated something that completely soaked, or filled to brim and cannot take any more.
The name of the ship that brought the settlers to Plymouth was the "Mayflower" and the document that most of its passengers signed was the "Mayflower Compact", which was enacted upon arrival.