WASHINGTON — Layer after layer of security measures that were supposed to block an intruder from getting into the White House all failed in stunning succession on the evening of Sept. 19, according to an internal review of a fence jumper’s breach.

There were nearly a dozen failures in the Secret Service’s rings of security that helped Omar Jose Gonzalez, 42, get inside the White House and deep into the East Room, according to a Department of Homeland Security review, a summary of which was obtained Thursday by The Washington Post.

In one example, a canine handler who was supposed to help chase down and tackle anyone who breached the White House compound was in a van on a personal cellphone call at the time and did not hear any radio traffic about a fence jumper. By the time he and his well-trained attack dog arrived, Gonzalez was already entering the White House front door, the review found.

In another failure, a crisis command center officer who thought he was alerting everyone to an intruder that Friday night didn’t realize his radio wasn’t working properly — meaning his alert was not being broadcast to officers stationed at the White House. Some alarms were also muted.

The end result: Many Secret Service officers were delayed in realizing a person had jumped the fence, and then weren’t sure where he was located. Construction on the north grounds obscured many officers’ views, further hampering their ability to spot trouble and respond.

An officer on the North Portico guarding the front gate also did not realize for some time that there was a fence jumper because of “unintelligible traffic over the radio,” the report said. With his gun drawn as he watched Gonzalez run up the steps, the officer let the intruder walk past him because he assumed the front door was locked; it was not.

Lawmakers said Thursday that they were shocked by the depth of the communication and protocol failures exposed by the report.

The review “reads as a comedy of errors by the U.S. Secret Service and confirms that fundamental reform is needed,” said Rep. Bob Goodlatte, R-Va., chairman of the House Judiciary Committee, which will hold a Secret Service oversight hearing Wednesday.

Secret Service spokesman Ed Donovan said the agency has already put in place or is in the process of implementing changes to fix the problems highlighted in the report.”

“The entire Secret Service workforce is dedicated to ensuring that we provide the highest level of protection to the people and facilities we protect,” Donovan said. “We must take this opportunity to make any necessary changes and improvements related to carrying out our protective mission to regain the trust of the American people.”

As outlined by the summary, things went badly that night from the very beginning.

President Barack Obama and his daughters were flying to Camp David, and had just lifted off in the president’s helicopter a few minutes before the breach.

The section of the fence that Gonzalez scaled lacked an ornamental spike — called a trident — that would have made it harder for him to get over, the report found.

Two emergency response team members responded to the commotion quickly with rifles pointed at Gonzalez but determined he was not a lethal risk because he appeared unarmed. The one who got closest to tackling him was surprised when Gonzalez barreled through a line of bushes at the base of the North Portico steps. He and several fellow officers had assumed the dense bush line was impassable.

The review, which was first reported by The New York Times, also found striking communications failures. The canine handler and his dog, for example, were stationed in a van partly to avoid giving the impression of a militarized zone to White House visitors. But it was not equipped with monitors or speakers to alert him of a breach.

An officer in the service’s Joint Operations Command Center saw alarm panels indicating that someone had breached the fence line and sent out an alert over the radio. But he didn’t know the command center radio system lacked the capability to override standard radio traffic, so his transmission was not broadcast. He avoided making additional transmissions because he wanted to keep the line clear for other radio reports.

The officer stationed directly inside the front door had no idea there was an intruder, as the alarm at her station had been muted at White House staff request. Gonzalez knocked her over as she tried too late to lock the front door. She reached for her baton to subdue him, but grabbed her flashlight by mistake.

Gonzalez had been questioned once by the Secret Service on the White House perimeter in August, and a Secret Service field office in Roanoke, Virginia had been warned about him by Virginia state police. Authorities had arrested him and discovered he had a map of the White House and multiple weapons and ammunition. But the field office did not notify Secret Service headquarters of this — a failing the review attributed to a lack of clear directives from headquarters.

Lawmakers said Thursday the review lays bare the pressing need for an overhaul of the Secret Service. The chairman of the House Homeland Security Committee, Michael McCaul, R-Texas, introduced legislation Thursday authorizing a “top-to-bottom” review of the agency.

Rep. Bennie Thompson, D-Miss., the committee’s ranking member, said the review shows that the response to Gonzalez was hampered “because of critical and major failures in communications, confusion about operational protocols, and gaps in staffing and training. While some of these problems can be attributed to a lack of resources, others are systemic and indicative of Secret Service culture.”