Former Secretary of State Hillary Clinton on Monday became the third Democratic presidential candidate to release a debt-free college plan, joining Sen. Bernie Sanders of Vermont and former Maryland Gov. Martin O'Malley in trying to increase Americans' access to higher education. Clinton's "New College Compact" aims to enable students to earn degrees at in-state public colleges without taking out loans for tuition. To do this, she'd orchestrate a partnership between states and the federal government where the former receive grants for lowering costs. 

"Higher education should be a right, not a privilege for those who can afford it," Clinton argued in a video posted Monday on YouTube. But while debt-free college initiatives may sound good in theory, they might not work so well in execution. Experts say the high cost of the proposals, as well as their potential to increase student enrollment and hurt graduation rates, are becoming worrisome as the candidates' ideas gain traction.

“If you’re doing this, you’re probably taking resources from other places, and sometimes within higher education,” said Robert Kelchen, an assistant professor of higher education at Seton Hall University in South Orange, New Jersey.

College affordability has already emerged as a major theme of the 2016 general election. Last year it cost an average of $18,943 for a student (for one year) to attend a public college in his or her state -- about three times more than it was 30 years ago. To keep up, students have turned to loans. Each student in the class of 2015 graduated with an average of $35,051 in loans, the most in U.S. history. The national total recently reached an all-time high of $1.2 trillion.

Voter concern has driven Democratic candidates like Sanders, O'Malley and Clinton to float debt-free college proposals. Republicans fired back, with former Florida Gov. Jeb Bush arguing that "more free stuff" is not the way to reform education. New Jersey Gov. Chris Christie said debt-free plans were a typical liberal approach to the student debt crisis. "If college graduates are going to reap the greater economic rewards and opportunities of earning a degree, then it seems fair for them to support the cost of the education they’re receiving," he said.

Conservatives also don't like what could be the biggest problem with the debt-free plans: the price tag. Clinton's initiative would cost an estimated $350 billion over the next 10 years, paid for by closing tax loopholes on wealthy Americans. Sanders' legislation would ask federal and state governments to give schools $70 billion a year to make up for tuition, mostly originating from a tax he'd impose on Wall Street transactions.

David Bergeron, a senior fellow for postsecondary education at the public policy and advocacy group Center for American Progress, said he worries that colleges will slash tuition and the government won't hold up its end of the deal. If schools find themselves tight on money, they could start making across-the-board cuts, he said. They could eliminate student advising systems or rely on online coursework instead of paying professors.

"There are tradeoffs," Bergeron said. "We can make the higher education system cost less by making it of less quality."

Even if they were fully funded, colleges and universities would likely have trouble coping with demand. Bergeron said he would expect to see enrollment increase as a result of debt-free tuition plans. Schools would either have to admit more students than normal and figure out how to handle them, or severely limit how many people they take by upping admission standards. Affluent, more academically proficient students might elbow out less college-ready, low-income ones, Bergeron said.

If the federal government is helping to cover the costs of a growing student body, federal officials could also want more say on how the money is spent, said Rick Hess, the director of education policy studies at the conservative think tank American Enterprise Institute in Washington, D.C. "You'll see federal policy attempting to tell colleges where and when they're allowed to cut," he said, listing off the possibilities: defunded libraries, more adjunct teachers, longer semesters. "We'd wind up with the federal government playing an uncomfortably central role."

Assuming that students are admitted and have access to resources, they still might not graduate on time. In a way, having to pay high tuition rates motivates young adults to get in and get out of school. Without that incentive, students might extend their time in college, Hess said. Germany, which has free tuition, struggles with this -- it has "Dauerstudenten," or eternal students that regularly take up to six years to earn undergraduate degrees.

It's all hypothetical at this point, but the debt-free college proposals mean one thing for sure: "We would be in an entirely different world," Hess said.