On the floor of the Republican National Convention Tuesday evening, vice presidential candidate JD Vance greeted and shook hands with excited delegates as he walked toward his seat.

It was a marked contrast from former President Donald Trump, who entered the hall a few minutes later and was separated from supporters by a column of Secret Service agents. His ear still bandaged after an attempted assassination, Trump closely hugged the wall. Instead of handshakes or hellos for those gathered, he offered fist pumps to the cameras.

The contrast underscores the new reality facing Trump after a gunman opened fire at his rally in Pennsylvania Saturday, raising serious questions about the agency that is tasked with protecting the president, former presidents and major-party candidates. Trump's campaign must also adjust to a new reality after he came millimeters from death or serious injury — and as law enforcement warns of the potential for more political violence.

Trump campaign officials declined to comment on the stepped-up security and how it might impact his interactions going forward.

“We do not comment on President Trump’s security detail. All questions should be directed to the United States Secret Service,” said Trump campaign spokesperson Steven Cheung.

Homeland Security Secretary Alejandro Mayorkas, whose agency oversees the Secret Service, said Monday that he could not discuss “specifics of the protection or the enhancements made, as they involve sensitive tactics and procedures. I can say, however, that personnel and other protective resources, technology, and capabilities have been added.”

The Secret Service had already stepped up Trump's protection in the days before the attack following an unrelated threat from Iran, two U.S. officials said Tuesday. But that extra security didn't stop the gunman, who fired from an adjacent roof, from killing one audience member and injuring two others along with Trump.

The FBI and Homeland Security officials remain “concerned about the potential for follow-on or retaliatory acts of violence following this attack,” according to a joint intelligence bulletin by Homeland Security and the FBI and obtained by The Associated Press. The bulletin warned that lone actors and small groups will “continue to see rallies and campaign events as attractive targets.”

Underscoring the security risks, a man armed with an AK-47 pistol, wearing a ski mask and carrying a tactical backpack was taken into custody Monday near the Fiserv Forum, where the convention is being held.

The attack has led to stepped-up security not only for Trump. President Joe Biden’s security has also been bolstered, with more agents surrounding him as he boarded Air Force One to Las Vegas on Monday night. Independent candidate Robert F. Kennedy Jr. also received Secret Service protection in the shooting’s wake.

Trump's campaign has also responded in other ways, including placing armed security at all hours outside their offices in Florida and Washington, D.C.

Trump has already scheduled his next rally in Grand Rapids, Michigan, on Saturday. That's where he will appear with Vance for their first event as a presidential ticket.

But the new posture complicates, at least for now, the interactions Trump regularly has with supporters as he signs autographs, shakes hands and poses for selfies at events and on airplane tarmacs.