In 2010, Republican Adam Kinzinger knocked off incumbent Deborah Halvorson in the 11th congressional district.
Again in 2012, he had to take on another incumbent in Republican Don Manzullo -- this time in the primary. Kinzinger, 34, a former Air Force pilot, was essentially moved out of his favored area and into the 2nd District when Illinois Democrats remapped. Kinzinger decided to switch into the 16th to take on another conservative Republican.
The strategy worked out so far as the Associated Press projects that Kinzinger has taken the 16th district with 56-percent of the vote (with 80% of precincts reporting.
For Manzullo, 2012 marked his first primary challenge in 20 years, and now the first time he'll be out of office in two decades.
Both candidates spent much of the election cycle arguing over who was the most conservative.
Manzullo, 67, grabbed endorsements from conservative groups that favored social issues. Kinzinger grabbed party stars like Eric Cantor, Aaron Schock and John Shimkus.