A plan to conduct a live artillery exercise over a major highway in Southern California, as part of a military event attended by Vice President JD Vance, sparked significant controversy. Governor Gavin Newsom expressed grave safety concerns, leading him to shut down a section of the heavily trafficked interstate on Saturday.

“The President’s actions prioritize ego over responsibility, showing a blatant disregard for public safety,” stated the Democratic governor. “Firing live artillery over a busy highway is not only irresponsible but also poses a serious danger.”

However, officials from the U.S. Marines defended the exercise at Camp Pendleton, asserting that the artillery firing was standard procedure and posed no real threat. They argued that closing Interstate 5, the key coastal route between San Diego and Los Angeles, was unnecessary.

The decision to close the highway drew criticism from Republican circles.

U.S. Representative Darrell Issa, whose district is located to the east of the military base, described Governor Newsom’s decision as “a needless publicity maneuver.”

Vice President Vance, a Republican and former Marine, along with Defense Secretary Pete Hegseth, were at the base in northern San Diego County to mark the 250th anniversary of the Marine Corps. They witnessed a display featuring amphibious vehicles and Marines executing a beach assault. The event included aircraft demonstrations and munitions strikes, providing a dramatic backdrop as Vance and his wife, Usha, observed the proceedings.

The state had considered closing the freeway earlier in the week, but the U.S. Marines said Thursday that the event would occur on approved training ranges and comport with established safety protocols.

State transportation officials ultimately made the decision to close the freeway after practice firings Friday evening and a request from event organizers for signage along the road stating “Overhead fire in progress.”

The California Highway Patrol closed a 17-mile (27 kilometers) stretch of the highway for periods before and during the Saturday exercise. Severe traffic delays were reported Saturday morning and early afternoon. No mishaps were reported related to the artillery fire.

“This is all because of the White House-directed military event, that for the safety of the public, we need to shut down the freeway since they’re sending live ordinances over the freeway,” California Department of Transportation spokesperson Matt Rocco said.

U.S. Marines Capt. Gregory Dreibelbis said in a statement that there is artillery fire at the base nearly every week and that the exercises didn’t endanger motorists.

“Weeks of deliberate planning and rehearsals ensured success at every phase of execution,” he said.

In a statement to The New York Times, a spokesperson for Vance, William Martin, said Newsom misled the public about the safety risk.

“If Gavin Newsom wants to oppose the training exercises that ensure our Armed Forces are the deadliest and most lethal fighting force in the world, then he can go right ahead,” Martin said.

Rocco said the I-5 closure could cost up to another two hours of trip time for those commuting between San Diego and Los Angeles. The freeway carries 80,000 travelers and $94 million in freight through the corridor daily, according to the governor’s office. Passenger rail services running parallel to the I-5 have also been canceled for the afternoon.