Sen. Bernie Sanders wants free tuition at four-year public colleges. Here’s why it won’t work.

But so much of what Sanders is calling for would take a level of enforcement and compliance that would be difficult to achieve, said Iris Palmer, a senior policy analyst at the New America Foundation. More importantly, she questioned whether free tuition would be sustainable if it encouraged more people to go to college. "What happens at the next recession when the money from Wall Street drops and the number of students enrolling in college swells? How could a program like this be sustained?" Palmer said. "And how would you keep institutions from consistently increasing what they say it costs to educate a student?"