Kelly Tshibaka, an Alaska official who on Monday launched a challenge against Sen. Lisa Murkowski, is backed by former aides to President Donald Trump in a race that could prove a test of his appeal agaist the GOP establishment.

Tim Murtaugh, the former communication director for Trump’s reelection campaign, Bill Stepien, Trump’s former campaign manager, Justin Clark, Trump’s former deputy campaign manager, and Nick Trainer, Trump’s former battleground states director, are all involved in Tshibaka’s campaign through their consulting firms. Stepien, Clark, and Trainer started a firm called National Public Affairs after the election.