While continuing his decreasingly plausible campaign for the Democratic presidential nomination, Sen. Bernie Sanders is keeping up the ideological pressure, hoping to tilt the party platform leftward, in the direction of his sweeping campaign promises on taxes, health care, Social Security and college tuition. That’s an internal matter for Democrats, to be sure, but also of interest to anyone who believes that political parties should offer realistic solutions.

In that sense, the prospect of a Sanders-ized platform is cause for concern. Sanders’ offerings to the American people are, quite simply, too good to be true, and much less feasible, politically or administratively, than he lets on. More expensive, as well.

The latest confirmation that Sanders’ plans don’t add up, fiscally, comes from a pair of reports by the nonpartisan Urban Institute and the Tax Policy Center, which is a project of the Urban Institute and the Brookings Institution. Analysts modeled the combined impact of Sanders’ proposals for a single-payer health plan, long-term care, free state university tuition, paid family and medical leave, plus increased Social Security benefits — and the tax increases he has proposed to pay for them. The good news is that the Sanders plan would redistribute resources quite progressively. The lowest-earning 20 percent of the U.S. population would gain net transfers equivalent to almost three times their current adjusted gross incomes. The net losers would be the top 5 percent — with AGIs averaging $656,241 — who would see an average loss of $110,994.

Alas, the bad news is bad indeed. Despite the substantial tax increases associated with Sanders’ policies, they would not be fully paid for — not even close. To the contrary, the tax hikes would be sufficient to cover just 46 percent of the spending increases, resulting in additional budget deficits of $18 trillion over 10 years. A deficit increase of that magnitude would cause an additional $3 trillion in interest payments over the same period — unless, of course, Sanders has another $18 trillion in tax increases or spending cuts up his sleeve.