Rep. Adam Kinzinger (R-IL) defeated fellow Rep. Donald Manzullo (R-IL) in a heated member-versus-member primary Tuesday. It was a race that highlighted the schism between competing wings of the Republican Party.

Kinzinger, a freshman, and Manzullo, who has served in the House for 10 terms, faced off due to Congressional redistricting.

What was already a tense race between two colleagues grew ugly as election day neared. It intensified after House Majority Leader Eric Cantor (R-VA) took the rare step of a party leader endorsing one of the lawmakers.

Cantor publicly threw his weight behind Kinzinger. Manzullo subsequently suggested that Cantor should step down from his leadership post for getting involved in the contest.

The race symbolized the intra-party tensions between the GOP leadership establishment and conservative grassroots activists. Kinzinger, 34, cast himself as a fresh face in Congress. Meantime, Manzullo, 67, associated himself with Tea Party loyalists.

Although Kinzinger won election to the House that year thanks to the conservative wave, along with an endorsement from former GOP vice presidential nominee Sarah Palin, many of those groups felt his voting record ultimately wasn’t conservative enough. Conservative activist groups such as the American Conservative Union (ACU), FreedomWorks and the Illinois Tea Party backed Manzullo in the primary.

Those groups also objected to Cantor’s involvement in the race, further cementing their views that Kinzinger abandoned them and had become a part of the Republican establishment.

Cantor insisted that his endorsement for Kinzinger wasn’t a personal slight to Manzullo.

“It is not about Don Manzullo. This is about Adam Kinzinger and the confidence I’ve got in him to represent the future of our party,” Cantor said in a March 8 interview on Special Report with Bret Baier.

The House Republican leadership considers Kinzinger a rising star, earning him a deputy whip position. Kinzinger often sided with leaders over the Tea Party, most notably during the summer 2011 debate to raise the debt limit. 

In addition to Cantor’s endorsement, House Speaker John Boehner (R-OH) and House Majority Whip Kevin McCarthy (R-CA) donated to Kinzinger’s campaign. However, Boehner also cut Manzullo $5,000 check late last week.

Kinzinger also had two prominent super PACs on his side during the primary. The Cantor-aligned super PAC, Young Guns Action Fund, conducted a $52,000 ad buy for Kinzinger. That further infuriated Manzullo. The Houston-based Campaign for Primary Accountability, which targets incumbents, also poured money into the race against Manzullo. 

Barring unforseen circumstances, Kinzinger is on track to win this fall too, with no Democrat on the ballot.