Sen. Bernie Sanders (I-Vt.). (Jay Paul/Reuters)

SEN. BERNIE Sanders (I-Vt.) delivered a forceful message in a speech at Liberty University on Monday: Inequality is too high, the wealth gap is immoral and rich people have rigged the economy.

Though hyperbolic, this message appears to be resonating: In a time of anxiety about the country’s economic future, the latest Post-ABC News poll shows Mr. Sanders cutting into Hillary Clinton’s once commanding lead for the Democratic presidential nomination.

Beyond the hyperbole, however, must be real policy. And on that score, this self-described socialist from New England is less progressive — in the real effect of his proposals — than he sounds. His promises, according to a new analysis from the Wall Street Journal, would cost the government an eye-popping $18 trillion over 10 years. Instead of carefully crafting policy to help those who need it, he would shower largess on young and old, poor and well-to-do.

For example: Mr. Sanders wants to make public college free for everyone. “We have in this country sufficient amounts of money to put more people in jail than any other country on earth,” Mr. Sanders said Monday. “But apparently we do not have enough money to provide jobs and education to our young people. I believe that’s wrong.”

Mr. Sanders seems to be echoing President Obama, who pointed out this summer that the $80 billion the country spends on incarcerating people could pay for universal pre-kindergarten education, a doubling of salaries for high school teachers or the elimination of public college tuition.

Of course, there’s only so much money that the government can realistically remove from the prison system. But say Mr. Sanders could take out $47 billion, the cost of the higher education bill he unveiled in May. Or say he found the money somewhere else — he proposed a financial transactions tax in the bill. Why would Mr. Sanders want to give any of those funds to the wealthy? Eliminating public college tuition makes it free for everyone, poor or rich, leaving less of that $47 billion to help low-income people who really struggle to pay for college, day care and other basic needs.

Mr. Sanders makes a similar misstep on the student debt “crisis.” He would drastically reduce the rate on new student loans and refinance existing loans on similarly generous terms. Yet plenty of college graduates go on to high-paying careers and do not need help with their loans. Federal education loan policy is already generous, given that students often have little to no credit history. Instead of lowering everyone’s rates, additional aid should be targeted at those who have trouble paying. Mr. Obama has tried to do this by tying repayment and forgiveness policies to post-graduation income, but the system could be improved.

Mr. Sanders identifies significant challenges, and we support higher taxes to meet some of them. But the political barriers even to modest new spending are formidable. A true progressive agenda would seek to dismantle those barriers, not create new entitlements for the upper middle class.