Hillary Clinton outside a coffee shop in Mount Vernon, Iowa. (Photo by Melina Mara/The Washington Post)

This story has been updated.

Liberal leaders are pressuring Hillary Rodham Clinton advocate a national plan for "debt-free college" in her presidential campaign, part of a broader effort to convince the Democratic front-runner to embrace pillars of Sen. Elizabeth Warren's progressive agenda.

The push comes as prominent Democratic senators and House members plan to introduce resolutions calling for the elimination of student debt at public colleges and universities on Tuesday, while progressive activists have scheduled events at 10 college campuses -- all in a coordinated push to promote debt-free college as a major issue in the 2016 presidential race.

Although Clinton is not expected to unveil a detailed policy agenda until later this spring or summer, she mentioned rising student loan debt as a focus of her campaign during her visit to Iowa last week. "There's something wrong when students and their families have to go deeply into debt to be able to get the education and skills they need in order to make the best of their own lives," Clinton said at a Kirkwood Community College in Monticello.

The debt-free college effort is being coordinated by the Progressive Change Campaign Committee, which says it represents "the Elizabeth Warren wing of the Democratic Party" and has been trying to pull Clinton to the left on a variety of economic and other issues.

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Warren (Mass.) is joining Sens. Brian Schatz (Hawaii) and Charles E. Schumer (N.Y.), a Clinton ally and the No. 3 Democrat in Senate leadership, as a co-sponsor of the debt-free college resolution. A House equivalent is being offered by Reps. Keith Ellison (Minn.) and Raul Grijalva (Ariz.), who co-chair the House Progressive Caucus, as well as Reps. Donna Edwards (Md.), Alan Grayson (Fla.) and two former chairmen of the Democratic Congressional Campaign Committee, Reps. Steve Israel (N.Y.) and Chris Van Hollen (Md.).

Neither the resolution nor the senators' statements directly mention Clinton or her campaign.

Schumer said he hopes the issue becomes "the next big idea" on the campaign.

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“Going to college is absolutely essential to getting into the middle class and getting ahead once you're there, but far too often it ends up breaking students' banks,” Schumer said. “When students graduate with loads of debt, the ripple effects are endless; they're less likely to start a business, to buy a house, and to realize their full potential. When it comes to making college affordable, I'm hopeful that debt-free college is the next big idea."

Officially, the effort is aimed at convincing all Democratic presidential candidates to advocate debt-free college. But the target of their advocacy clearly is Clinton, who so far is the party's only announced candidate and is in a commanding position to win the nomination.

The PCCC is organizing events on 10 college campuses, including two in Iowa (University of Northern Iowa and Iowa State University) and two in the New Hampshire (Keene State College and University of New Hampshire). The states hold the nation's first presidential caucuses and primary election respectively.