Peter Newman is a special agent for the President.
There should be no real doubt in anyone's mind that the prototype for Peter Newman is Oliver North. Newman is a Marine attached to the White House in a Special Operations capacity, charged with operating under covert conditions to fight the nation's enemies.
While North's primary emphasis while working for Reagan was procuring arms for the Contras fighting in Nicaragua, Newman's chief enemy is international terrorism. Against them, he is a tenacious and determined as North was. He mainly has to dodge the bullets and bombs of Islamic radicals while North dodged Congressmen and news anchors.
Just over 6' tall and ramrod straight, Newman is 38 years old but look considerably younger. A graduate of the Naval Academy, he served in numerous trouble spots around the world, being promoted early for his bravery and his accomplishments. He fought during the Gulf War where he was injured by shrapnel, earning a Purple Heart, as well as the Navy Cross. He is married as the series begins, though that is going through trouble, with no children. Newman is a proud member of a Force Reconnaissance company, the Marines Special Forces.
In the first book, he is just being assigned to work for the National Security Advisor though he had tried to not be. He would have preferred to be leading troops in the field, not working for a man who greatly disliked anyone in uniform and denigrated not only their accomplishments but also their actual profession. Orders, however, are orders and he goes where he is directed.