Harris said Trump "intends to enact what in effect is a national sales tax -call it a Trump tax - that would raise prices on middle class families by almost $4,000 a year."
Trump has said that he would propose a 10% tariff on all non-domestic goods sold in the U.S. While tariffs are levied separately from taxes, economists say that much of their impact would be passed along to consumers, making them analogous to a tax.
Harris' figure about how much it will cost families is higher than current estimates.
The American Action Forum, a center-right think tank, has projected additional costs per household of $1,700 to $2,350 annually. The Peterson Institute of International Economics, another Washington, D.C.-based think tank, projected that such tariffs would cost a middle-income household about $1,700 extra each year.