So now at least there’s a primary on the Democratic side. Bernie Sanders is in. And Martin O’Malley is announcing later this week that he’s doing the same.

It all hardly means that Hillary Clinton is likely to lose the nomination—the chances of that have just shot up from 0 percent to, what, 3.8 percent. Still, she will have to fight for votes now. Alabama isn’t likely to lose to Coastal Carolina, but at least it’s a game, and Coastal Carolina shows up and fights, and Alabama has to get out there on the field and execute.

The thing that is commonly said about Sanders and O’Malley is that they can push Clinton to the left, but I’m not sure even that is true. At best, it’ll depend on the issue. Take the Pacific trade deal. My expectation is that Clinton will eventually announce that she’s for it. Given that her State Department helped negotiate it, that would seem the logical place for her to land.

But even if she did come out against it, is it going to be because of Sanders and O’Malley? I say doubtful. It’s going to be because it becomes clear to her campaign that she forfeits more among liberals in enthusiasm than she gains among centrists in credibility or donations or what have you. That has more to do with the grassroots and the unions and a certain non-candidate (Elizabeth Warren) than it does with her opponents.

But all that said, here’s the important thing that long-shot candidates can bring to the dance: They can introduce an issue or way of seeing a problem that voters just weren’t thinking about before and the front-runner won’t have the fortitude to talk about because it’s seen as too risky. And even if they don’t get the front-runner to embrace their position, they can create a reality in which the candidate gets asked a lot of questions about it and with any luck it becomes a position she ultimately has to embrace.

In free college for all, Sanders has the issue. Some caveats: First of all, “free” doesn’t necessarily mean completely free, and “for all” definitely doesn’t mean for all. Sanders means free when he says free, but some liberal higher-education experts wonder whether totally free is a wise course of action—an education has a value, after all, and surely some price point is reasonable. So maybe “really inexpensive” would do just fine. But as for the “for all” part, even Sanders doesn’t mean that. He’s talking about public universities only. So Penn State yes, Penn no, UCLA yes, USC no, and so on.

There are reasons to proceed with caution here, because such a proposal would have enormous knock-on effects. The downsides would hit small private colleges—and many of these are singular and valuable institutions in this country—hard. The really elite private schools probably wouldn’t feel much impact, but the smaller ones would almost certainly have to lower their tuition, and they just aren’t built for that right now. If UNC-Chapel Hill and NC State became free or near-free, it wouldn’t hit Duke, which is a national school; but it would harm and even threaten the existence of some of North Carolina’s smaller 30 or more private schools.

But even so, that could all be finessed. The far bigger problem we face as a nation is crushing student debt, which is up around a staggering $1.2 trillion. Tuition costs have been rising far higher than inflation, and even far higher than health-care costs—almost twice as fast. And the most important statistic of all in many ways: Since the economic meltdown especially, state governments have cut back dramatically on aid to higher education. Washington has stepped in to pick up some of this slack, but state legislatures used to really care about their public universities, before the Koch Brothers started buying them up (the legislatures, I mean). More states simply have to return to the old vision of seeing their universities as the great public trusts they are.

Sanders’s bill would address this last point by requiring states to pay for one-third of the (surprisingly modest, by my lights) price tag of around $70 billion. The feds would pay the other two-thirds. That’s about $47 billion. As higher-ed expert Jordan Weissman has written, Washington now spends about $60 billion a year administering and funding its various student loan programs. In theory it’s just a matter of moving some of that money around, although the higher education world, like any other, has extremely powerful lobbyists—the private schools and the for-profit schools both lobby heavily—so reform would be a heavy lift.

But let’s give Sanders big props for putting this out there. I hope this becomes the center of his stump speech, and I hope he uses his time on those six debate stages to push it. It’s my sense that it could be pretty popular—especially among Democratic primary voters, but I think even among independents and some Republicans, once it’s explained to them that the cost isn’t nearly as high as they probably think it is. I’m not sure most people would buy “free,” because of the folk wisdom about there being no such thing as a free lunch. However, the idea that a public-university education should be something that a kid ought to be able to pay for by working a summer job? I think 85 percent of the country would back that. And if Sanders can effectively press his case for a few months, maybe Hillary will back it, too.