I-5 in Carlsbad, California, on Oct. 18, 2025

A major southern California highway was shut down for a U.S. Marine Corps demonstration on Oct. 18. The event pitted California Gov. Gavin Newsom against the federal government yet again.

Interstate 5 shut down from Harbor Drive to Basilone Road, a stretch of the main artery over 15 miles, from 11 a.m. to 3 p.m. local time, according to the California Highway Patrol. Vice President JD Vance and Secretary of War Pete Hegseth attended the event at Camp Pendleton, commemorating the Marines' 250th anniversary.

The news comes after days of back-and-forth between Gov. Gavin Newsom, federal officials and the Marines over whether the demonstration would require any roads to close.

Standing atop a seven-ton military truck with his wife, Vance watched the largest Marine exercise in a decade on Oct. 18, featuring F-18 and F-35 flyovers, parachute landings, Navy Seals swimming ashore, offshore destroyers and amphibious ships, simulated village explosions, and MH-60 helicopters dropping additional Seals over the water.

The Marines said in a statement earlier in the week that the event would take place "on approved training ranges and comport with established safety protocols."

"No public highways or transportation routes will be closed," the statement said.

Current Operations Officer for I Marine Expeditionary Force Capt. Gregory Dreibelbis told USA TODAY in an email that the Navy-Marine Corps team coordinated closely with state agencies to ensure the amphibious demonstration could proceed safely without closing I-5 or rail transit, underscoring the Marines’ ongoing partnership with Southern California communities and their commitment to maintaining combat readiness through regular live-fire and amphibious training.

Car, rail delays throughout Southern California

Interstate 5 is the primary connection between coastal San Diego County and Orange County. The busy freeway travels directly through the Camp Pendleton Marine Corps base for nearly 20 miles, with no other major thoroughfares in the region.

The Marines told USA TODAY in a statement on Oct. 18 that it did not request the closure.

"We appreciate the public’s patience as Marines and Sailors conduct realistic training during today’s historic Amphibious Capabilities Demonstration, showcasing the strength and unity of the Navy-Marine Corps team and ensuring we remain ready to defend the Homeland and our Nation’s interests abroad," the statement reads.

An Oct. 18 California Department of Transportation (Caltrans) news release called it an "unscheduled closure."

“Because of the event and closure, drivers should expect delays on Interstate 5 and other state routes throughout Southern California before, during, and after the event,” Caltrans said. The governor's office said 65,000 vehicles cross between San Diego and Orange counties each day using the route.

In addition to the coastal freeway, officials said Southern California rail service along the route, which runs from San Diego to Los Angeles, would also be disrupted in the afternoon.

Aerial footage by ABC 7 showed I-5 backed up with congested traffic due to the closures. The freeway reportedly reopened briefly before closing again. By 3 p.m., the freeway had opened.

'Absurd show of force'

Newsom called the demonstration an "absurd show of force." The shutdown was decided because of "extreme life safety risk and distraction to drivers, including sudden, unexpected, and loud explosions," Newsom said.

"The President is putting his ego over responsibility with this disregard for public safety. Firing live rounds over a busy highway isn’t just wrong – it’s dangerous," Newsom said in a statement. "Using our military to intimidate people you disagree with isn’t strength – it’s reckless, it’s disrespectful, and it’s beneath the office he holds. Law and order? This is chaos and confusion.”

Newsom said Caltrans received a request from the event organizers to display signage along I-5 that reads "Overhead fire in progress." State officials also observed live munitions being fired near the freeway on Oct. 17 in an apparent test run, the governor said.

Marines fire artillery regularly

The military news outlet Task and Purpose, citing a Marines statement, reported the artillery exercise was scheduled for 1:30 p.m. local time, which included M777 howitzer cannons firing from west of the 5 into designated ranges east of the freeway.

Marines fire artillery nearly every week, from High Mobility Air Rocket Systems (HIMARS) to M777 howitzers, Capt. Dreibelbis said. Live-fire training sessions occur regularly at the battery and small-unit levels. At the regimental level, large-scale artillery exercises occur twice per year.

The Marines have used the M777 howitzer since 2005, Dreibelbis said, adding it’s been “safely and effectively employed” in combat operations, such as in Syria.

“This amphibious demonstration is what Marines and Sailors train for every day,” he said. “Weeks of deliberate planning and rehearsals ensured success at every phase of execution, underscoring the Navy-Marine Corps team’s ability to safely conduct complex amphibious operations.”

'No accountability, no planning'

Rep. Mike Levin, a California Democrat whose district includes Camp Pendleton, said on social media that public safety and the Marine Corps' reputation are "far more important than the political agendas of J.D. Vance or Pete Hegseth.

"We can and should celebrate the Marine Corps in a manner that honors their proud legacy without compromising safety or community wellbeing," he said.

On social media, San Diego County Supervisor Jim Desmond, a Republican representing Camp Pendleton and surrounding communities, said the “freeway shutdown shows exactly what’s wrong with politics.”

“No accountability, no planning — just finger-pointing while everyday people sit in traffic, miss work, and watch their plans fall apart,” he said.

(This story was updated to add new information.)

Contributing: Zac Anderson

This article originally appeared on USA TODAY: Highway shuts down as Marines’ show sparks clash with Newsom

Reporting by Jeanine Santucci and Eduardo Cuevas, USA TODAY / USA TODAY

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