Hillary Clinton has something for everyone in President Obama’s political coalition, and this week her target is millennial voters. On Monday the inevitable Democratic presidential nominee, er, candidate rolled out a $350 billion proposal that she says will make college more affordable. The irony is that she plans to ramp up the federal subsidies that have for decades driven up the cost of a higher education.

Her campaign is selling the New College Compact as ground-breaking, but you’ll recognize the path: debt-free public...