If you build it, they will come. And in border enforcement, if you build it higher, they will still come.

That was part of the hard look Wayne Cornelius, director of the Center for Immigration Studies at UC-San Diego, took at the effectiveness of U.S. border enforcement in a talk at Stanford on Thursday.

Cornelius founded the Mexican Migration Field Research and Training Program, which studies immigration from three Mexican regions: Jalisco, Oaxaca and the Yucatan. Forty years of field research in Mexico and the U.S. provided him with first-hand accounts of legal and illegal immigration.

More than 4,800 surveys show illegal border crossing remains high although the U.S. has spent $17.1 billion on immigration enforcement this year alone, he said. Sixty percent of immigrants crossing the US-Mexico border succeed on their first try and 90 percent of those actually detained by border patrol still end up successful.

He added that border patrol has increased four-fold since 1992, adding 600 miles of fencing that costs up to $16 million per mile.

“It’s our own great wall,” Cornelius said, referring to a section in the Otay Mountains of San Diego County.

But rather than stopping illegal immigration flow, the fences have only diverted it, he said. Migrants can simply tunnel under, climb over fences or trek across deserts or the Rio Grande. In fact, smuggling migrants has increased drastically as prospective immigrants search for new and safer, though sometimes more expensive, ways to cross the border.

These detours have generated close to14,000 deaths, he said. “It’s a slow-motion death across the Southwest.”

Cornelius suggests a cheaper alternative to current U.S. border policy: a more generous guest work program, an increase in permanent legal immigrant admissions and an increase in the number of green cards the U.S. awards.

Cornelius’ statistics were compelling enough to astonish some members of the audience.

“I was really surprised to hear the incredible amount of spending that has gone into border enforcement with almost no results to show for it,” Omar Media ’13 said. “That’s $30 billion down the drain. This only reinforces the idea that the U.S. must adopt comprehensive immigration reform now. We can’t afford not to.”