Thamina Stoll’s graduation from Duke University this spring was a bittersweet moment for the Munich-born political science major.

On the one hand, she had just earned a degree from a school that she loved — and one she chose to attend over some Ivy League schools.

On the other hand, the terms of her continued U.S. residency became a lot more complicated with her expiring student visa.

“At the end of the day, I know that being international and not having a green card makes things significantly more challenging, especially if you haven’t majored in economics, engineering or computer science,” she says. “I feel like I can live up to my potential here to a much greater extent than I’d be able to do in Germany. And it’s just frustrating to witness how having the wrong passport makes everything so much more difficult.”

Employers and analysts have argued it would behoove the U.S. economy to establish a better immigration system to allow graduates like Stoll to stick around — especially considering a record-high 6 million job openings sat unfilled in the U.S. at the end of April, according to the Bureau of Labor Statistics.

By loosening the reins on immigration — or constructing a clearer path for college graduates to remain in the country — it’s been argued that American productivity would be jump-started, generating more substantial economic growth.

“Immigration brings diverse skill sets that keep our workforce flexible, help companies grow and increase the productivity of American workers,” said a letter written to Congress and President Donald Trump in April from a group of 1,500 economists, including a half-dozen Nobel laureates and several high-ranking officials from previous presidential administrations.

More than 1,040,000 international students were enrolled at U.S. colleges and universities during the 2015-2016 school year, according to the Institute of International Education. International students like Stoll made up 5.2 percent of all those enrolled in degree-granting institutions that year.

But the structure of the current immigration system forces many of these international graduates to leave the country after school if they haven’t found a willing visa sponsor. Stoll, with a degree in political science, found visa sponsorship hard to come by for someone outside of the tech sector.

“I received a couple of interview invitations. However, in two or three cases, they offered me an interview and made me fill out a candidate information sheet. And once they discovered I was international, they retracted their interview offer,” she says.

Stoll ended up locking down a fellowship opportunity through Duke’s Sanford School of Public Policy. And through the government’s Optional Practical Training program, she bought herself another 12 months to find a visa sponsor. But the clock is ticking for her to find a more permanent job and avoid going back to Germany.

“It’s not as if I want to live off of social welfare. If I wanted to do that, Germany has a pretty great system, at least compared with the U.S. I do want to contribute to this country, to this economy. And I do want to have an impact,” she says.

U.S. Citizenship and Immigration Services maintains strict guidelines on the number of visas doled out each year. And H-1B visas granted to skilled immigrants for more technical positions are also capped at 65,000, though an extra 20,000 H-1Bs can be distributed to individuals who have earned a U.S. master’s degree or higher. But the current system is governed by a lottery that doesn’t necessarily reward skill and experience.

And even once someone locks down one of these visas, his or her permanence in the U.S. isn’t guaranteed. The country’s current green card backlog can leave qualified individuals already working or studying in America waiting in the wings for years, experts say. During that span, H-1B holders that have been in the country for a decade or more can’t start their own companies or branch off from their day jobs without fear of jeopardizing their legal residency.

[READ: These Are the Best Best Countries to Be an Immigrant]

“At the end of the day, it’s about the locking up of human potential,” says Rishi Bhilawadikar, a senior user experience designer at a San-Francisco-based e-commerce company. “You have a trained workforce that is present here legally, that is extremely skilled, that has a lot of experience working as a direct employee with American corporations and most of the time educated in American universities.”

Bhilawadikar arrived in Indiana in 2005 to pursue a master’s degree in video game design. He secured an internship in Silicon Valley in 2007 and eventually found himself working in California as an H-1B holder.

But he says the process of assimilating into a new culture — all while wrestling with the sense of impermanence associated with the current visa system — isn’t an easy one and is not well understood by those who haven’t gone through it. So he decided to take it upon himself to raise awareness. While working his demanding Silicon Valley job, Bhilawadikar used nights and weekends to write and produce a feature film titled “For Here or To Go?”, which tells the story of the trials and tribulations faced by an aspiring Indian entrepreneur living in Silicon Valley and working on an H-1B visa.

The H-1B and L-1 visas — which allow foreign workers at international companies with offices in the U.S. to come over and work on a limited basis — are not without their dark sides. Companies in some cases have used these visa programs to displace U.S. workers with lower-wage international labor.

Mike Emmons, a 55-year-old informational technology worker living in Orlando, witnessed the more treacherous side of the U.S. immigration system firsthand during his time at Siemens 15 years ago. Emmons says he was one of about 20 workers who were told by senior management that they would be let go. To earn a severance package, he says, they were told they would have to train their L-1 and H-1B visa-holding replacements.

“Many of my coworkers — some had masters degrees, multiple certificates in SAP programming — they were sent packing,” he says. “We shouldn’t be training our foreign replacements.”

Emmons has been a vocal opponent of the current H-1B and L-1 visa systems, testifying before Congress in 2004 after losing his job at Siemens. Though Bhilawadikar argues reform should better accommodate immigrants, Emmons thinks the system should be retooled to make it more difficult for international workers to supplant American employees. He quickly found other work when he lost his job, but the prospects of not having health insurance or steady income were daunting for a father with a physically disabled daughter to care for.

“[A]s long as they’re giving these visas away for cheap, cheap, cheap, companies are not going to want to hire Americans,” he says.

The government maintains regulations and restrictions on visa holders’ compensation, and employers typically face thousands of dollars in costs associated with bringing on an H-1B worker. A poll published by the American Competitiveness Alliance last year indicated 82 percent of the U.S. companies surveyed face costs equal or higher costs in hiring a foreign worker than they do in hiring a domestic employee.

But businesses have still found ways to cut corners — something Bhilawadikar says he’s keenly aware of as a visa holder.

“[Immigration] has certainly been loopholed and abused in the system,” he says. “They certainly need to have a greater degree of scrutiny. But it’s not on the individuals who are trying to come here, because that’s what the promise of America is. You come here for a better life. And I think you see the blame falling on individuals completely. It’s a capitalist economy at the end of the day. There’s demand that arises out of businesses to cut costs.”

Lawmakers have indicated a willingness to tackle the problem, however. A bipartisan bill introduced earlier this year would require employers to raise their minimum pay for certain types of H-1B workers in an attempt to dissuade companies from bringing on new workers simply to save money. A separate bill would tweak the current H-1B lottery system by introducing a “preference system” designed to give a “leg up” to foreign students “educated in the United States” and to advanced degree holders.

As Stoll attempts to lock down a more permanent home in the U.S., she says she hopes to simply get the message out that something needs to change.

“So many people are not even aware of these issues and the struggles international students go through on a daily basis,” she says. “And when I tell someone about this, they say, ‘This is ridiculous. We need someone like you in this country.'”

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The U.S. Immigration System Faces Criticism From All Sides originally appeared on usnews.com