House Majority Leader Eric Cantor today threw his weight behind freshman Rep. Adam Kinzinger in his primary fight against fellow Republican Rep. Don Manzullo in Illinois’ 16th district.

The Virginia Republican endorsed Kinzinger in a joint statement with Rep. John Shimkus (R-Ill.). “Adam Kinzinger is hands down the candidate the conservative cause needs to win the primary for Congress on March 20th and he has our enthusiastic endorsement for a second term in Congress,” the two lawmakers argued.

Although the statement does not directly name Manzullo, who has served 10 terms in the House, Cantor and Shimkus take a glancing shot at their colleague.

“We work on a regular basis with both Adam Kinzinger and his opponent. We join our colleague Congressman Aaron Schock of Illinois in the judgment that Adam Kinzinger is the right choice to keep advancing our conservative movement,” they said.

It is unusual for members of leadership to openly intervene in primaries, particularly those involving two incumbents.

The contest between Manzullo and Kinzinger is one of 13 expected races this cycle featuring two incumbents. The first Member-vs.-Member race was decided this week, with Ohio Democratic Rep. Marcy Kaptur defeating Rep. Dennis Kucinich in a primary. The Illinois primary will be the next Member-vs.-Member contest to be decided.