Who is Senator Sedgewick Sexton from Deception Point and what is their importance?

Senator Sexton is the republican hopeful for President of the United States. When the book opens, he is ahead of the current President in the polls. The cornerstone of his campaign has been rallying against NASA and their overspending. At every opportunity, he takes advantage of any mistake or overspending on the part of NASA and admits that if he were President, he would shut down the space agency and divert funding to educational programs.