Up till now, Hillary Clinton has dismissed Bernie Sanders’ plan for tuition-free college as expensive and unnecessary, going as far to quip that she doesn’t “think taxpayers should be paying to send Donald Trump’s kids to college.”

Now she’s making an almost 180-degree turn. Today, Clinton announced an expansion of her education platform. Though it still won’t give Trump’s kids a free education, it’s notably more generous than the one she previously outlined—and it’s a near copy of Sanders’ plan for free college.

Under Clinton’s new plan, public colleges would, by 2021, be free for all students from families that make less than $125,000 a year—so that only the top 15% or so of American households by income have to pay for college. Sanders was quick to praise Clinton for “the very bold initiative.”

But while Clinton’s new policy idea may win her a bunch of Bernie supporters, it, like Sanders’ original plan, faces tremendous obstacles to seeing the light of day.

For one, the plan is unlikely to pass in a Republican-controlled Congress. For another, it’ll be enormously expensive. The campaign hasn’t told reporters (paywall) what the plan will cost nor how it will be paid for, but last year Clinton priced her previous, more modest “college affordability” plan at $350 billion (to be covered by closing high-income tax loopholes). Sanders’ plan was pegged at $750 billion in federal money alone, with more from the states. Clinton’s new plan, too, will require states to cough up, and they could refuse.

Whatever the feasibility, Clinton’s sudden change of heart reveals exactly how urgent an issue the cost of college has become in the US. There’s good reason the matter is taking center stage in the upcoming presidential election: Student loan debt is currently at $1.3 trillion, and rising.