Sanders doesn’t just call for incremental steps toward single-payer. He’s proposing to shift all of health care to federal taxes in one fell swoop. That’s one reason for the enormous, sudden increase in taxes the plan would require—$1.38 trillion on top of existing federal spending, according to Sanders’ own estimates. As Harold Pollack has pointed out, that $1.38 trillion is just about equal to total federal income and estate tax collections in 2014—in other words, the plan would require doubling that revenue. Sanders insists that he’s shown how he would pay for it through a 6.2 increase in payroll taxes (which he calls an “income-based premium paid by employers,” though the cost will fall on employees); a 2.2 percent increase in income taxes on everyone; higher estate taxes; taxing capital gains and interest as ordinary income; limiting tax deductions for the rich; and higher income-tax rates on the upper brackets (which, combined with other increased taxes he’s also calling for, would bring the top marginal federal rate to 77 percent, as Dylan Matthews shows at Vox).
But Sanders’s estimate of the needed increase in taxation, despite its whopping size, is too low. The plan would actually cost another $1.1 trillion a year, according to an analysis by Kenneth Thorpe, a health-care economist at Emory University, who has long experience working with single-payer proponents. In 2006, the Vermont legislature hired Thorpe to cost out a single-payer proposal, and in 2014 progressive legislators in Vermont hired him again. So this is not an estimate from an economist generally opposed to universal health care or to single-payer. Thorpe’s estimates indicate that workers would have to pay an additional 20 percent of compensation to pay for Sanders’s plan.