In February 1992, less than three months into his first stint as the federal government’s top lawyer, Attorney General William Pelham Barr told a gathering of more than 100 law enforcement officials in San Diego that under his leadership, the U.S. Department of Justice would finally solve the looming immigration crisis at the border.

Barr’s proposed solution was, in its way, decades ahead of its time: the construction of a heavily armored steel fence along the U.S.-Mexico border immediately south of San Diego, complete with lighting, motion sensors, and the addition of hundreds of Border Patrol agents.

The fence was not “a silver bullet,” Barr admitted in his speech, but “a steady march in the right direction” to preventing undocumented immigrants from entering the country with impunity.

Unfortunately for Barr, the fence was an epic failure.

Though Barr saw the barrier as a novel way to stop undocumented immigrants from “crashing through the back door and the back window, violating our laws, flouting our sovereignty and ignoring our process,” as he told law enforcement in that speech, border-crossers took little notice of the latest hurdle.

“It doesn’t matter how many people, horses, bicycles, helicopters or planes they use,” one migrant told The Washington Post one week after Barr’s speech. “People will go. It doesn’t matter if the fence is electric—we’ll fry, but we’re still going.”

Migrants simply hopped it, dug under it, sprinted past Border Patrol when they weren’t looking, or walked its length to enter the United States through the rougher terrain of the San Ysidro Mountains. And they’ve been doing so ever since.

“The deterrent effect of tens of billions of dollars in investments in Barr’s approach to immigration control never materialized,” said Professor Wayne Cornelius, an expert on the mass politics of immigration at the University California, San Diego, who criticized Barr’s proposal at the time as a “Keystone Kops” approach to immigration enforcement, both inflammatory and ineffective.

The fence’s manifest failure remains a major indication that Barr, now nominated to serve as attorney general once again under President Donald Trump, will be an enthusiastic supporter of the centerpiece of Trump’s immigration policy—a proposed border wall that is 1,986 miles longer than Barr’s own unsuccessful iteration.

But a failure to learn from the mistakes of three decades ago, Cornelius said, could leave American taxpayers on the hook for repeating an expensive mistake.

“Nine out of ten migrants who weren’t discouraged from leaving home and coming to the U.S. border were not kept out of the country,” Cornelius told The Daily Beast. “[Barr’s] 1992 project is evidence that he has been a hard-liner on immigration enforcement for most of his government career—his policy preferences haven’t evolved.”

“Congress should know that if they vote to confirm,” Cornelius said.

So convinced was Barr that the 14-mile fence was all that was needed to slow the stream of undocumented immigrants entering the country into a trickle that, two weeks after its announcement, he told PBS NewsHour that presidential candidate Pat Buchanan’s proposal to erect a barrier along the entire U.S.-Mexico border amounted to a hat on a hat.

“I don’t think it’s necessary,” Barr told Jim Lehrer. “I think that’s overkill to put a barrier from one side of the border to the other… Illegal immigrants do not cross in the middle of the desert and walk hundreds of miles to the nearest city.”

Barr confidently pointed to his own barrier as having “reduced violence and made it easier to interdict the aliens crossing” within a matter of weeks, a belief he clung to even years after the fence failed to meaningfully reduce the number of undocumented immigrants who successfully entered California from Mexico.

“Good steps were taken, and the Bush administration was getting a lot more control over it, including putting up the fences,” Barr told the University of Virginia’s Miller Center in an expansive 2001 interview about his tenure at the Department of Justice, in which he defended the fences as having “cut down substantially on immigration.”

“I devoted a lot of effort and energy to doing our best to shut down the border in California,” Barr said of his time overseeing Immigration and Naturalization Services, the government agency later succeeded by Citizenship and Immigration Services, Immigration and Customs Enforcement, and Customs and Border Protection. “We kept on pushing them further west, and then eventually you get them going over long stretches of open ground, and once you get them out of the cities…”

But the assertion that Barr’s border fence succeeded in stemming migration into the United States from Mexico, Cornelius said, did not bear out in subsequent field studies of the region, which revealed that roughly 90 percent of undocumented migrants hoping to gain entry into the country succeeded in entering the United States on their most recent trip to the border.

If confirmed as the new attorney general, Cornelius said, “we can expect Mr. Barr to be one of the undaunted cheerleaders for Trump’s approach to immigration policy. If he and his colleagues are successful, taxpayers will once again be stiffed.”

A spokesperson for the Department of Justice declined to comment on whether Barr learned any lessons from the 1992 fence’s failure, but by all indications, the Trump administration views Barr’s supervision of the fence fiasco as a positive.

“He’s an outstanding man,” Trump told law enforcement officials in early December, hours after officially naming Barr as the nominee to succeed the beleaguered Jeff Sessions as attorney general. “During his tenure, he demonstrated an unwavering adherence to the rule of law... There is no one more capable or more qualified for this role.”