It’s official:  Hillary Clinton will not be unopposed for the Democratic presidential nomination. Sen. Bernie Sanders of Vermont has decided to make challenging Clinton his first act as a full-fledged member of the party. Heretofore an independent, the self-described democratic socialist has caucused with the Democrats both in the Senate and when he was in the House. Now he’s jumping into the presidential race “because America needs a political revolution,” as he put it on Twitter.

The logic of Sanders for president is that the revolution must begin with a struggle for the soul of the Democratic Party so that it remains progressive — and unmixed with the business-friendly economic policy and overly militaristic foreign policy for which the Democratic left wing often reproaches Clinton. Presumably, Sanders would achieve this objective one of two ways: Either he wins or he pressures Clinton to commit herself to a more left-leaning agenda on her way to victory.

There’s much to like about the Sanders agenda, at least in broad outline. He’s right to denounce money in politics as a “disgrace.” Ditto for his promise to push climate change up the list of national priorities. Income inequality is, indeed, a big challenge, as Sanders says — one that would only worsen if Republican cuts to the estate tax and other upper-income breaks he so energetically opposes were to become law. When it comes to debating new Democratic approaches to these issues in the primary, we say the more the merrier.

On certain points, however, we already know enough about Sanders’s ideas to hope they don’t prevail. He is a particularly simplistic opponent of U.S. global leadership in general, and of President Obama’s free-trade agenda in particular. He backs an increase in Social Security benefits, paid for with a massive tax hike on the rich that would shore up the elderly but leave little for other, more pressing needs.

Indeed, this is only one way in which Sanders’ socialist revolution would channel scarce resources to the non-needy. With the U.S. population aging and health care costs rising, a true progressive agenda should focus on how to bring opportunity to those most in need. Instead, to take another example, Sanders would devote $18 billion per year in federal funds, with state matching funds, so states could offer two years of free tuition at public universities to all students, apparently without regard to income. Yet discounted in-state tuition already subsidizes college for the sons and daughters of many families making well above the median income — using the tax dollars of many families making less than the median.

If it’s going to be built on promises like these, we wouldn’t want to be a part of Sanders’ revolution.