Former U.S. Rep. Peter Roskam, who recently joined Sidley Austin LLP as a partner, has only lost two elections during his 25-year career in elected office.He was defeated by Judy Biggert in 1998 in his bid to represent Illinois’ 13th District in the U.S. House of Representatives. Most recently, in November, Roskam lost his congressional seat to Democrat Sean Casten.Before his 12-year stint representing Illinois&rsquo …