White House senior adviser Stephen Miller vowed Monday that the Trump administration will do everything in its power to root out the left-wing organizations that have fomented political violence, following the assassination of Charlie Kirk.

During an appearance on a special tribute episode of “The Charlie Kick Show” hosted by Vice President J.D. Vance, Mr. Miller said the final text he received from Mr. Kirk was focused on coming up with an organized strategy “to go after the left-wing organizations that are promoting violence in this country.”

“We are going to channel all of the anger that we have over the organized campaign that led to this assassination, to uproot and dismantle these terrorist networks,” Mr. Miller said, citing the doxing of public officials and organized street violence. “It is a vast domestic terror movement.”

“With God as my witness, we are going to use every resource we have at the Department of Justice, Homeland Security, and throughout this government to identify, disrupt, dismantle, and destroy these networks and make America safe against the American people,” he said. “It will happen, and we will do it in Charlie’s name.”

An evangelical Christian and co-founder of the youth organizing group Turning Point USA, Mr. Kirk was shot and killed last week during an appearance at Utah Valley University.

The 31-year-old has been credited with reshaping the conservative movement by attracting more young people to the cause and emphasizing the importance of debate. Police have charged 22-year-old Tyler Robinson of Utah with the murder.