While the Senate will likely pass legislation to protect unpaid interns working in the federal government from sexual harassment and discrimination, interns in the private sector might not be so lucky.

The Democratic-sponsored bill, which cruised through the Republican-controlled House of Representatives on Monday night, would grant unpaid interns in the federal government protection under the Civil Rights Act — meaning that interns could sue the federal government if they experienced discrimination or sexual harassment on the job.

"It's nonsensical that interns don't have all of the protections other employees have," Reid Setzer, a policy analyst at advocacy group Young Invincibles that has lobbied on the issue, told Mashable. Between 500,000 and a million people are unpaid interns each year, according to widely quoted stats from The Atlantic.

The bill would buck a 1994 precedent stemming from a lawsuit filed by Bridget O'Connor, then an unpaid intern at Rockland Psychiatric Center. O'Connor alleged that a supervisor suggested she participate in an orgy, asked her to remove her clothing before speaking to him and dubbed her Miss Sexual Harassment.

But a federal appeals court ruled that because O'Connor wasn't getting a salary, she couldn't be classified as an employee — and she didn't have the right to sue.

Since then, only a handful of states and Washington, D.C. have passed legislation to protect unpaid interns from discrimination and sexual harassment. The issue largely flew under the federal radar until Reps. Elijiah Cummings (D-Md.), Bobby Scott (D-Va.), and Grace Meng (D-NY) introduced the package of bills in July.

"We’ve seen this intern economy grow and grow," David Yamada, a professor of law at Suffolk University who authored one of the first papers on the legal rights of interns, tells Mashable. "The law has been a step behind this development as we’ve created this sort of gray area between school and full-time employment."

There's something wrong with the world when your parents will pay you to clean the house and internships want you to work 20+ hours unpaid. — Stacy (@petiteanastasie) December 31, 2015

Yamada said that he expects the federal bill to pass through the Republican-controlled Senate — after all, the federal law would affect a smaller number of interns than the private sector bill.

But Yamada and others' forecast for the companion bill that would grant the same rights to interns working in private businesses, which Scott called on the Education and Workforce Committee to look into on Monday, isn't so rosy — because the Republican-controlled Congress is reluctant to place more restrictions and controls on businesses.

Yamada says he expects trade associations and other companies that support businesses to lobby against the bill. Camille Olson, a management-side employee attorney, says that the private sector legislation could be costly and unattractive to private sector companies.

"When those protections are expanded to include unpaid interns, companies incur an expense in corresponding changes to their policies and training to ensure compliance, which may prove to be cost-prohibitive for the traditional unpaid intern model, particularly when quantifying the risk of litigation in addition to the cost of compliance," Olson said.

The private sector might make some companies reluctant to hire unpaid interns, Olson says.

But I always learned &appreciated more at my unpaid internships...being at the White House and working on Capitol Hill always felt surreal — R A C H A E L (@seaux_southern) August 17, 2015

"The vast majority of companies that engage interns would need to revise their policies and practices to include interns within them," Olson says. "That may result in fewer interns being engaged and potentially fewer opportunities for college students to get experiences and exposure to various industries."

But while this legislation would grant unpaid interns protection from sexual harassment and discrimination, it wouldn't grant them protection under the Fair Labor Standards Act, which regulates the number of hours employees can work. So interns' legal status would still be...well, complicated.

And the legal questions surrounding wages on unpaid internships are already plentiful.

In 2010, the Labor Department said it would more aggressively regulate unpaid internships, setting up a six-step criteria — which has been panned for being too vague and confusing, with criteria like "the internship experience is for the benefit of the intern" — to determine whether for-profit companies need to pay their interns. But, as ProPublica noted, very few companies have actually been cited by the department for failing to pay interns.

Courts haven't had a clear consensus on the issue, either. Some companies have had to pay up big time for not paying their interns. In March, Viacom agreed to pay $7.2 million to settle a suit alleging that its unpaid internship program violated state and federal wage laws, while NBC forked over $6.2 million in June.

But in July, a U.S. Court of Appeals said that Hearst and Fox Searchlight didn't need to pay its interns. Notably, Fox Searchlight had support — in the form of a "friend-of-the-court" brief — from the U.S. Chamber of Commerce, which Yamada suggested might make a play with trade associations to prevent the private sector bill from passing Congress. (Reps for the Chamber of Commerce didn't respond to Mashable's requests for comment on the legislation.)

Tl;dr: while some labor activists agree that the House legislation will be a small victory to granting rights to interns, don't expect questions about unpaid internships to go away anytime soon.

"You've really got this murky legal soup," Setzer says. "There will still remain outstanding legal questions as to how they'll be classified."

"It’s taking a lot of time," Yamada says, "but I think it’s also important to remember that the legal challenges to unpaid internships only started to bubble up in the past couple of years. It’s been an issue that’s been under the radar screen for so long."