Who is Sterling Mulkern from A Drink Before the War and what is their importance?

Senator Sterling Mulkern hires Patrick to find the “documents” that Jenna Angeline stole from Senator Paulson's office. He's known Patrick's family for years. When Mulkern realizes that Patrick knows the truth about Paulson raping Roland, he does his best to convince him that Paulson is a “good politician”. After paying Patrick's bill, he is furious to discover that Patrick has given the story to reporter, Richie Colgan.