There was a lot discussed at the GOP primary debate on Thursday—combative comments from the party's front-runner, clashes over NSA surveillance—but only one presidential hopeful, Florida Sen. Marco Rubio, had anything to say about student debt, and none approached the subject of college affordability.

Seventeen Republican candidates met at the Quicken Loans Arena in Cleveland, Ohio, for the first nationally televised debates of the 2016 presidential election season, hosted by Fox News, and they answered a range of questions regarding their positions on issues such as immigration, national security, and job growth. The issue that received almost no attention also happened to be one of the most important issues to young people, many of whom are currently drowning in student debt.

Rubio made brief mention of his own personal history with student loans in an effort to demonstrate that Democratic candidate Hillary Clinton was not in a position to criticize him over the issue—but he failed to follow up with any actionable plans on how he'd address the problem.

"If I'm our nominee, how is Hillary Clinton gonna lecture me about living paycheck to paycheck?" Rubio wondered. "I was raised paycheck to paycheck... How is she gonna lecture me about student loans? I owed over $100,000 just four years ago."

The senator graduated from the University of Florida and the University of Miami Law School, the latter ranking in the top-25 for law school graduates that have the most debt, according to U.S. News and World Report. He appeared to understand the significance of the issue, yet the conversation quickly shifted away from subject after Rubio had said his piece.

But at least Rubio mentioned student debt. As for the other nine candidates, the issue just didn't seem to be a priority, and that's despite the fact that college affordability is the number one most important economic issues for young voters, as the Pew Research Center determined.

Of course, the issue has been previously addressed by several of the candidates, including Rubio, who introduced a bipartisan measure last year aimed at reducing student loan debt. The Dynamic Student Loan Repayment Act was designed to consolidate and simplify income-based repayment options for graduates who owned money on federal student loans. Ohio Gov. John Kasich supported legislation that would reduce tuition costs at public college in his home state; New Jersey Gov. Chris Christie has gone on the record supporting the expansion of education programs such as the Supplemental Education Opportunity Grant.

The Republican candidate and real estate tycoon leading the polls, Donald Trump, knew full well how important college affordability is to young people, telling the Hill in an exclusive interview that “[O]ne of the biggest questions I get is from people in college [about student loans]... They’re in college—they’re doing well but they’ve got student loans up to the neck. They’re swimming in these loans.” But even though he was granted the most speaking time among the other nine hopefuls on the stage, he declined to mention it even once. Trump has also been criticized for incorporating a for-profit college business model into his own for-profit college, Trump University, which became the subject of a lawsuit in 2013.

To win over young voters, it stands to reason that these candidates should stop dodging one of their biggest priorities. It was only the first debate of the season, but the lack of conversation surrounding student debt and college affordability was telling.

For more coverage of the Republican debate, check out these links:

Here are the Winners and Losers From Last Night's Debate

Donald Trump's Remarks on Women Raised Eyebrows in the First GOP Debate

The One Shocking Issue That No GOP Candidate Mentioned in the First Debate

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