Border Patrol agents are threatening to leave the critical federal agency en masse if Vice President Kamala Harris wins in November — with several agents telling The Post they can’t face four more years of being undermined and scapegoated.

“I won’t do that again… four years of hell,” said one agent, who is far from retired.

Another agent said: “A lot of guys who can retire will leave. If Trump wins, they will stay.”

On Monday, the border patrol union, the National Border Patrol Council, endorsed former President Donald Trump.

The Border Patrol has suffered massive turnover and plummeting morale under the Biden-Harris administration, insiders say.

The agency has laid off more than 4,000 people since October 2020, leaving about 19,000 employees, according to the Washington Examiner.

Incentives such as increasing recruiting incentives from $10,000 to $30,000 and encouraging retired officers to return have not filled the void.

Both Trump and Harris have pledged to strengthen the Border Patrol, with the Republican candidate announcing an increase in staffing by a third, or 10,000 new agents, on Sunday.

But several agents, who spoke to The Post anonymously for fear of backlash from their bosses, said Harris would likely take office because of a massive personnel crisis within the agency if she were elected.

“We will have another exodus simply because we will have a bunch of agents for 20 years who will say peace,” one agent said.

He also thinks the most experienced agents — with five to 10 years of experience and who do much of the Border Patrol’s heavy lifting — will use their skills to get other jobs.

“We will have another exodus simply because we will have a bunch of agents for 20 years who will say peace,” the agent said.

The agent, who is no closer to retiring, said he was “absolutely sure” he would leave the Border Patrol if Harris led the government.

“Under this administration, they have done everything they can to make our work as ineffective as possible. They can’t outwardly tell us not to do our job, but when you see criminals coming in and being released, it sucks,” one of the officers said.

Declining morale led the agency to hire its first suicidologist to help combat the rising suicide rate within Customs and Border Protection, which includes the Border Patrol.

In 2022, the agency recorded a record 15 suicides.

“Morale has never been lower within the Border Patrol, but under the Biden-Harris administration and its current ads, acting like it’s pro-border security is just rubbing salt on the wound already gaping for morale among Border Patrol agents and law enforcement,” former Yuma Border Patrol Chief Chris Clem previously told The Post.

“Kamala Harris has been bad for morale, not only for law enforcement across the country, but also for our border security personnel.”

The number of migrant encounters nationwide under the Biden-Harris administration has surpassed 10 million, according to federal data.

Illegal crossings have reached new levels in recent months following new restrictions on asylum at the U.S.-Mexico border.

Border Patrol agents stationed at the U.S.-Mexico border saw about 56,000 crossings in July; 58,000 in August; and 54,000 in September – compared to 250,000 in December 2023.