Students walk across campus at the University of Vermont on Monday, April 30, 2012 in Burlington, Vt. U.S. Rep. Peter Welch is compiling stories about student debt. Welch was at the University of Vermont on Monday where he met with students, some of whom are working multiple jobs and studying full time as they accumulate student loan debt. In Vermont, almost 70 percent of college graduates have an average of $30,000 in debt. (AP Photo/Toby Talbot)
FILE - Students walk across campus at the University of Vermont in Burlington, Vt.

Ben Wagner worked three days a week for his congressional representative this summer in northern Virginia. 
A senior at the College of William and Mary this fall in Williamsburg, Virginia, Wagner was busy reaching out to constituents, answering phone calls and conducting research for U.S. Representative Jennifer Wexton, a Democrat. 
He said the experience helped define his future. 
"I realized that that's what I want to do," Wagner said. "Be on the Hill. Be a staffer. Run a campaign." (The Hill refers to Capitol Hill in Washington, D.C.) 
And he couldn't have done it without the people who provided him food, housing, transportation and health insurance: his parents. Wagner worked as an intern for free. 

Democratic presidential candidate Sen. Barack Obama, D-Ill., center, poses for photos with Senate interns, Wednesday, July 9, 2008, on Capitol Hill in Washington.

"I really have to thank my parents," he said. They knew that "taking this internship, whether or not it was unpaid, was something that I needed to do in order to advance my career to the next step." 
Wagner was one of an estimated hundreds of thousands of unpaid interns in the U.S.   
But "it's a huge privilege," he said. 
Gaps in apprenticeships 
Internships can be traced to apprenticeships of the Middle Ages, where craftsmen trained unskilled labor in a trade. Currently, at least 60% of college graduates have completed an internship, according to the National Association of Colleges and Employers (NACE). 
And in 2014, 46.5% of internships were unpaid. 
Unpaid internships were protected by the U.S. Department of Labor in 2018 when it instituted the "primary beneficiary test," which allows unpaid internships if the intern receives a greater benefit from the experience than the employer. 
An internship is the most important credential for entering the job market, according to a Chronicle of Higher Education study in 2012. Employers often value experience more than academics, such as a college major or grades.  
And it pays off after graduation. 
"Recent studies have indicated that students graduating with internship experiences, in general, are more likely than students without those experiences to find employment upon graduation," wrote the NACE Journal in May 2017. 
"What we can notice is a lot of interns become these successful individuals," said Guillermo Creamer, deputy director of Pay Our Interns, a nonprofit group that seeks more paid government internships.  
Creamer cited former intern Dennis Muilenburg, now chief executive officer of Boeing, U.S. Representative Ayanna Pressley of Massachusetts, U.S. House Speaker Nancy Pelosi and South Bend, Indiana, Mayor Pete Buttigieg, a Democratic candidate for president. 
"An internship is a gateway to the workforce," Creamer said. "That's the way we have to look at it." 
But, he added, the gateway is not accessible to everyone. 
Costs of an internship 
Unless interns are living at home, they must find a way to pay for housing, food and transportation. Top cities by population — New York, San Francisco, Los Angeles, Chicago and Washington — offer the most internships, according to job-rating platform Glassdoor. According to the Bureau of Economic Analysis, these cities are among the most expensive in the country.

In this Tuesday, June 19, 2012 photo, Maria Darrow, of Falmouth, Maine, right, who will start her sophomore year at Amherst College in the fall, plants strawberries as part of her paid internship at a community farm in Amherst, Mass. The 20-year-old…

Erin Johansson, research director of Jobs With Justice, a nonprofit organization that advocates for workers' rights, said she believes unpaid internships limit employment equality. 
While there is insufficient research on internships, said Philip Gardner, director of the Collegiate Employment Research Institute at Michigan State University, students who take unpaid internships are generally from lower-income families.  
"The majority of kids who take unpaid internships are middle or lower class" and tend to be the first membrers of their families to attend college. "They want to work for a [non-government organization] and in public service or social justice," which typically pay less, Gardner said.  
Higher-income students from families with $120,000 annual income are more likely to be found in paid internships with for-profit companies. Because internships are often a chance for employers to test out future employees, and a pathway for interns to jobs and income after college, the higher-income students do better after graduation. 
"Jobs should be accessible to everybody," said Johansson of Jobs With Justice, which pays its interns to avoid a "class system" that favors the privileged. 
Creamer said that he and Pay Our Interns co-founder Carlos Mark Vera — both first-generation Americans and first-generation college students — were motivated to start their campaign by what they saw as a lack of diversity when they were Capitol Hill interns, affectionately known as Hillterns. 
"Too many individuals didn't look like us," Creamer, who like Vera is Hispanic, said about the congressional interns. "We wanted to challenge that." 
"The majority of people who can't take advantage of these opportunities are people who can't afford them, and that tends to fall greatly in the minority community: in the Latino community, in the African American community. You've got individuals from disadvantaged backgrounds and they tend to be people of color," he said. 
'Different perspectives' 
Johansson said this means businesses and organizations "really miss out on having people that, if they pay them, could be bringing different perspectives that aren't often in our world." 
Without those perspectives, she said, professionals often "don't understand what average people go through in the working world." 

FILE - Students students walk outside the Pauley Pavilion basketball arena at the University of California-Los Angeles, Nov. 15, 2017.

"Many for-profit and government agencies, especially at the federal level, are misusing the unpaid internship," wrote Gardner in 2010 in a report for Intern Bridge, a website that offers information for interns and strives to create and improve internships in the U.S. "It is hard to rationalize why some of the leading investment banks, broadcasting companies, movie production companies, and Congress have elevated the unpaid internship because of the coveted prestige for their positions. These sectors need to set a better example, especially Congress.” 
Last year, with the help of Creamer and Vera's advocacy, they did. Congress allocated $14 million between the two chambers to pay Hillterns who work in Washington. Each member office is allotted $20,000 to pay interns in the House Paid Internship Program, according to a House Administration Committee aide.  
"No qualified candidate should have to turn down the opportunity to intern on Capitol Hill in order to make ends meet," the aide wrote in an email. "In providing these funds, the House is making an important first step in breaking down the economic barrier to those seeking entry-level work on Capitol Hill. By expanding this opportunity for public service, it's our hope that qualified candidates for these internships will now have opportunities they did not have before."