An H-1B visa is reserved for foreign workers in specialty fields who have a job offer from a U.S. employer. Though the visa holders can work in any field, they’re especially prevalent in tech and other STEM jobs, including AI. Top companies including Amazon, Meta, and Salesforce have sponsored tens of thousands of H-1B workers over the past few years alone.

The visas have become a talking point among anti-immigration conservatives. Donald Trump controversially suspended the program temporarily while in office, while presidential hopeful Vivek Ramaswamy said he would “gut” the program and create an “actual meritocratic admission.” Other critics say recipients take away jobs from Americans.

But tech leaders, many of whom spoke out against Trump’s visa freeze, say the U.S. actually has the opposite problem: Rather than restricting the H-1B program, it should be expanded. Currently, 65,000 visas—a figure that hasn’t changed in more than two decades—can be awarded each year via a lottery, while another 20,000 can go to those who earn a graduate degree in the U.S.

Demand is overwhelming supply: In 2023, hundreds of thousands of applicants were denied. That hurts those workers, of course, but also companies, says Allison Ahern Fillo, a Boston-based immigration attorney. Some companies she represents are forced to apply for a visa for the same job candidate multiple years in a row.

“It’s really unfortunate that a U.S. employer wants to be able to employ someone and it’s really up to chance,” Fillo tells Fortune. “They vetted the person; they’re the right person for the job.”

Aaron Levie, CEO of cloud company Box, recently wrote on X that the discrepancy between demand and the number of visas granted should “make you go insane.”

“We are actively shooting our future selves in the foot,” he wrote. Levie did not respond to Fortune’s request for an interview.

This chart should make you go insane. This is the number of high skilled workers that want to work here. There is a cap at 85,000 slots that will be filled. We are actively shooting our future selves in the foot. pic.twitter.com/kYA8BDhzHC

— Aaron Levie (@levie) January 4, 2024

Research has found that hiring these migrant workers doesn’t adversely affect the economy, as some allege, but rather leads to further job creation and economic growth for myriad reasons: These workers drive innovation, pay U.S. taxes, start new businesses, and so on.

Restricting immigration ultimately harms companies and slows wage growth. Research by Britta Glennon, a professor at the University of Pennsylvania, finds that when companies cannot fill the roles with U.S. workers and are unable to hire highly skilled foreigners, they actually offshore more jobs.

“Microsoft has found that for every H-1B hire we make, we add on average four additional employees to support them in various capacities,” Bill Gates told members of Congress back in 2008.

Advocates of increasing the cap on visas also note that it’s not just the tech sector that would benefit: There’s plenty of demand in fields like medicine and scientific research where there simply aren’t enough American candidates.

What makes increasing the cap even more crucial, Fillo says, is that the H-1B visa is one of the only ways for educated foreigners to work in the U.S. at all—and eventually become residents or citizens.

“When we can’t hire and retain the top non-native talent, we hand global competitors what used to be America’s greatest edge,” Ben Zweig, a labor economist and the CEO of Revelio Labs, previously wrote for Fortune. “Solving this issue will help firms get the talent they need, help our cities grow, and create a more efficient and fairer workforce.”

Recent changes to visas

The Biden administration has made a few changes to the program in the past year unrelated to raising the cap, including allowing some applicants to renew their visas in the U.S., rather than requiring them to travel to their home country and renew it at a U.S. consulate.

U.S. Citizenship and Immigration Services also made changes to the annual lottery. In recent years, USCIS found that the same applicant was being submitted by multiple companies in order to game the system and increase their chances of being selected. This year, an individual can only enter once.

Additionally, the Biden administration has proposed a change that would require an applicant’s job to be “directly related” to their studies, and to the needs of any given job. Immigration experts say that could make things more difficult for visa holders who don’t necessarily end up with a job in a field related to what they studied. They are also proposing allowing entrepreneurs to sponsor themselves.

And of course, there are other objections to the program. Some critics have accused employers of exploiting the program, and using it to hire foreign workers while firing U.S. employees. Others worry the foreign workers themselves are the ones being exploited, and that the process is overly onerous on workers and businesses alike.