The issue of making college tuition-free has recently come to the fore in American politics, largely because the two leading contenders for the Democratic presidential nomination, Bernie Sanders and Hillary Clinton, have each championed it. Sanders has called for free undergraduate tuition at public colleges and universities, to be financed by a tax on Wall Street speculation, while Clinton has done the same, although with some qualifications and a different funding mechanism.
The major argument for free public college and university education is the same as for free public education in general: like the free public elementary and high schools already existing in the United States, free public higher education provides educational opportunity for all.