A day after a group formed to draft Elizabeth Warren to seek the 2016 presidential nomination, the Massachusetts senator riled up student activists with a speech on her bill that would let them refinance loans at lower rates.

The legislation would be paid for by raising income taxes on those making more than $1 million a year and would help about half of those at the Make Progress National Summit, as measured by a show of hands from the attendees with debt.

"This really does boil down to three words: Billionaires or students?" Warren said at the Washington conference. "We have to jump in now and make our own change."