President Trump, Vice President JD Vance, and numerous dignitaries, conservative figures, prominent reporters, television anchors, and up to 100,000 members of the public are expected to attend the tribute to Kirk's life this Sunday at State Farm Stadium, home of the Arizona Cardinals, in Glendale.

The Secret Service has been under serious scrutiny since multiple failures provided an opening for two near-miss assassination attempts against Trump last year, the first of which resulted in the death of rallygoer Corey Comperatore and the serious injury of two other attendees.

The Secret Service successfully protected the inauguration of President Trump in January without a hitch, even though the agency moved the swearing-in ceremony indoors and canceled the traditional outdoor parade, purportedly because of low temperatures in D.C.

But the massive Arizona memorial service honoring Kirk, the assassinated conservative activist and organizer known for his influence with young people across the country and the world, poses a serious challenge for law enforcement and the Secret Service, an agency already facing manpower strains and pressure as it strives to repair its reputation to execute a zero-fail mission.

The stadium in Glendale can seat 63,400, and the local police department is planning for a crowd of up to 100,000 people to descend on the area, with at least one overflow location designated at the Desert Diamond Arena where the event will livestream on jumbotrons.

Kirk's memorial comes during tumultuous times for the nation. His supporters mourn his brutal killing amid a national debate over gun violence and what types of limits, if any, private and government entities can place on free speech. Conservative and liberal politicians and political commentators are facing off over ABC's Wednesday decision to abruptly fire late-night talk show host Jimmy Kimmel after he misrepresented the assassin's likely motives for murdering Kirk. And Trump on Wednesday designated the far-left Antifa group a "terrorist organization" and said he was strongly recommending that those funding the movement be thoroughly investigated "in accordance with the highest legal standards and practices."

It's also a difficult moment for the Secret Service, which has faced serious retention issues since the assassination attempts, with a recent Department of Homeland Security Department Office of the Inspector General's report exposing the agency as seriously understaffed when it comes to counter snipers – 73% below mission requirements.