Ten Democratic state lawmakers on Monday announced their support for allowing students to graduate from college without incurring student loan debt. In doing so, the lawmakers join 99 members of Congress who have formally endorsed the idea of debt-free college, as well as all three Democratic presidential contenders.

The announcement came in a call organized by the Progressive Change Campaign Committee. The PCCC said it is aiming to convince Democrats across the nation to unite around debt-free college as part of what the group calls an "Elizabeth Warren-style" agenda, which it hopes will help Democrats win in coming elections.

The state legislators come from Hawaii, Illinois, Iowa, Massachusetts, Missouri, New Hampshire, Ohio, South Carolina, South Dakota and Wisconsin. In a sign that progressives have a long way to go before the idea of debt-free college gains mainstream traction, the lawmakers are only proposing non-binding resolutions stating their support, rather than legislation containing concrete measures.

More than 40 million Americans collectively owe roughly $1.3 trillion on their student loans, making student debt the second-largest source of household debt after home mortgages. Democrats have latched onto debt-free college as a way to deal with rising college costs and strapped household budgets.

Nearly 1 in 5 Americans with a student loan is in default, according to the Consumer Financial Protection Bureau. Millions more are either delinquent or otherwise delaying payments due to temporary hardships, allowing their burdens to grow as interest accumulates on top of their loan balances, according to the Department of Education. Federal financial regulators, including the Federal Reserve, worry that high student debt burdens risk slowing economic growth as households reduce consumption and limit other types of borrowing.

The three main Democrats vying for the party's 2016 presidential nomination -- Sen. Bernie Sanders (I-Vt.), former Maryland Gov. Martin O’Malley and former Secretary of State Hillary Clinton -- have all endorsed debt-free college and offered varying proposals aiming to make it a reality. Generally speaking, implementing debt-free college involves increasing federal and state spending while pressuring colleges to cap or reduce student costs.

But the concept doesn't have universal support among Democrats. The Obama administration, for example, wants to make community college nearly free for millions of Americans, but hasn't come out explicitly against student debt. During Education Secretary Arne Duncan's nearly seven years in office, total student debt has roughly doubled.

Some of the lawmakers who participated in the PCCC call said they're trying to build further support for debt-free college before introducing bills that would codify it. Others said debt-free college needs further study.

"It's a momentum-builder," said Massachusetts state Rep. Paul Mark about his resolution. Mark added that he's working on related legislation to aid student borrowers.

Iowa state Rep. Chris Hall said his decision not to offer specific legislation was in part an effort spur further debate.

"If you launch it as a resolution, you bring more people into the discussion," Hall said.

Katrina Shankland, a state representative from Wisconsin, said her endorsement would be accompanied by a call to create a state commission to study the proposal.

Many of the representatives face an uphill climb to get even the largely symbolic measures backed by their legislatures, particularly those dominated by Republicans. 

In South Carolina, for example, it's unlikely that the GOP-controlled state legislature will support Rep. Gilda Cobb-Hunter's debt-free college resolution, which she described as "extremely difficult to pass." 

Of the states represented by the ten lawmakers, six have state legislatures fullycontrolled by Republicans. Out of the remaining four, Illinois, Massachusetts and Iowa have Republican governors. Only Hawaii's state government is firmly controlled by Democrats.