Elizabeth Warren on Monday unveiled a sweeping plan to cancel most student loan debt while making public colleges tuition-free. Senator Warren’s plan would cost $1.25 trillion, to be funded by her proposed “ultra-millionaire” tax—an annual 2% tax hike on 75,000 U.S. households with $50 million or more in wealth. Vermont independent Senator Bernie Sanders made free public college a cornerstone of his 2016 campaign—and now his 2020 White House run—though Senator Warren says her idea goes further.