WASHINGTON — President Donald Trump and his top advisers are escalating their attacks on their opponents in the wake of Charlie Kirk’s killing, placing the blame for political violence on Democrats alone and signaling a broad crackdown on critics and left-leaning institutions.

Trump blamed the “radical left” almost immediately after Kirk was shot, before authorities had identified a suspect. He promised to find those responsible for political violence, as well as the “organizations that fund it and support it.”

Trump has an expansive view of those he deems radical, applying that term to almost all of his political adversaries. In his second term, Trump has pushed the boundaries of his authority to exact retribution on political opponents and institutions.

The death of Kirk, a popular young conservative activist, has added fuel to Trump’s campaign against his opponents. He and his administration have promised to bring the killer to justice while using the moment to blame the left — and only the left — more broadly.

Critics of the administration now worry that Kirk’s killing could be used as a pretext to move even more aggressively against those who speak out against Trump.

Authorities were still working Saturday to discern a motive in the killing. The suspect had recently spoken with a family member about the fact that Kirk was going to hold an event in Utah, according to a police affidavit, and he and his relative discussed “why they didn’t like him and the viewpoints he had.”

America in recent years has seen a wave of violence across the political spectrum, targeting Democrats and Republicans, but Trump has focused only on attacks against conservatives and his allies. On Friday, he appeared to excuse right-wing radicals by arguing that they were motivated by a desire to reduce crime.

And while the president has provided few specifics about how he plans to address rising political violence or mete out punishments, several administration officials vowed to scrutinize speech by those who have denounced Kirk — a self-declared supporter of free speech — and his often inflammatory views.

Defense Secretary Pete Hegseth said that his agency was closely tracking any military personnel who celebrated or mocked Kirk’s death, and Christopher Landau, the deputy secretary of state, suggested the administration would strip visas from individuals who celebrated Kirk’s death.

“I want to underscore that foreigners who glorify violence and hatred are not welcome visitors to our country,” Landau wrote on the social platform X.

On Capitol Hill, Rep. Clay Higgins, R-La., said he would use his congressional authority to seek immediate bans for life from social media platforms for anyone who “belittled the assassination of Charlie Kirk.”

“I’m also going after their business licenses and permitting, their businesses will be blacklisted aggressively, they should be kicked from every school, and their drivers licenses should be revoked,” he wrote on X. “I’m basically going to cancel with extreme prejudice these evil, sick animals who celebrated Charlie Kirk’s assassination. I’m starting that today.”

Trump also renewed his call Friday for prosecutors to file racketeering charges against George Soros, one of the Democratic Party’s biggest donors.

Trump and his allies have long claimed without evidence that Soros foments violent protests.

“We’re going to look into Soros because I think it’s a RICO case against him and other people because this is more than protests,” he said on Fox News. “This is real agitation; this is riots on the street — and we’re going to look into that.”

A spokesperson for Soros’ organization, Open Society Foundations, denied the allegations and called the threats “outrageous.”

Stephen Miller, a top adviser to the president, characterized the current moment in America as a battle between “family and nature” and those who celebrate “everything that is warped, twisted and depraved.”

He said the “fate of millions depends upon the defeat of this wicked ideology.”

In an interview Thursday with Scott Jennings, a conservative radio host, Susie Wiles, the White House chief of staff, said that before Kirk’s death, the administration had been working on “a more comprehensive plan on violence in America, the importance of free speech and civil speech,” though she did not provide any details. White House officials also declined to answer questions about the plan.

Experts warn that the polarization in the country is growing increasingly dire.

“We’re watching grief, anger, blame and calls for retribution all occurring in parallel and all occurring in the public sphere,” said Sean Westwood, an associate professor of government at Dartmouth College and the director of the Polarization Research Lab.