Earlier this week, the Hoover Institution released its findings in a new quarterly survey of 25 immigration policy experts. The survey examined the intersection of immigration and national security with particular attention given to policies that might reduce undocumented immigration to the United States.

Disappointingly, the prospects of a guest-worker program were not mentioned on the list of potential solutions to undocumented immigration. This oversight leaves unexamined the most efficient and sensible way to reduce illegal immigration: expanding legal immigration.

According to the Hoover, 83 percent of the scholars agreed that providing legal status for undocumented immigrants would improve immigration policy. Less than 40 percent thought stronger interior enforcement and deportations would lessen undocumented immigration.

Surprisingly, 68 percent of respondents agreed that mandatory E-Verify, the nationwide work-eligibility verification system, could be a potential solution. Cato’s Alex Nowrasteh, who took part in the Hoover survey, and his Cato colleague Jim Harper, recently published a Policy Analysis that found that E-Verify doesn’t work, hurts American workers, and leads to more identity theft.

Interestingly, not a single respondent thinks securing the border would be the most effective policy to reduce undocumented immigration. While it’s politically popular to call for enhanced border security, the truth is that nearly half of undocumented immigrants have overstayed their legal visas and thus would not be prevented from immigrating with a more secure border.

Furthermore, only 13 percent of the panel believes the benefits of a 100 percent secure border would outweigh the costs.

While the survey does its job in teasing out the problems with the border security solution, as noted, its biggest problem is lack of recognition of the likely prospects of reducing undocumented immigration through a guest-worker program.

The United States has had policies that decreased the undocumented population at a rapid rate. During World War II and the 20 years after, the U.S. government launched the bracero program to address wartime agricultural labor shortages. The program channeled guest workers into a legal and regulated system, shrinking the illegal immigrant population by 90 percent. More than 4.5 million Mexican workers took advantage of the program.

Stuart Anderson of the National Foundation for American Policy writes, “By providing a legal path to entry for Mexican farm workers the bracero program significantly reduced illegal immigration. The end of the bracero program in 1964 (and its curtailment in 1960) saw the beginning of the increases in illegal immigration that we see up to the present day.”

Critics may argue that guest workers may actually expand the illegal population by remaining in the country. Recent Niskanen Center research calculated that upwards of 97 percent of all guest workers leave after the allotted time determined by their visas. The undocumented population is bolstered mostly by those overstaying vacation or student visas and not guest workers, who would not take the chance of losing future opportunities for work permits.

In addition to being feasible, guest-worker programs are also supported by public opinion. Earlier this year Niskanen Center policy analyst Dave Bier found that, from 2001 to 2014, Americans supported foreign workers 56-34 percent. Other polls have found similar results.

Finally, a guest-worker program makes economic sense. In 2010, an Immigration Works and Chamber of Commerce report found that, “small, medium, and large employers in every region of the country count on the H-2B guestworker program to keep their businesses open and growing, creating opportunities for U.S. workers.” Their study also found that guest workers don’t depress the wages of native-born Americans.

One section of the Hoover survey asked the scholars for a tweet-length answer for how to limit undocumented immigration. Nowrasteh said the U.S. should “create a guest worker visa program to channel would-be illegal immigrants into a legal market.” It’s a simple concept that would reap significant returns on reducing illegal immigration and improve the U.S. economy.