In picking Paul Ryan, Mitt Romney has doubled down on his own campaign promise to give big tax breaks to the wealthy, uniting himself with a candidate who goes even further to do so: While Romney would bring taxes for top incomes down to 28 percent, Ryan has proposed bringing the top rate down even lower, to 25 percent. Meanwhile, Ryan’s plan would actually increase the effective tax rate on the very poorest Americans by getting rid of tax breaks that benefit low earners.

Under Ryan’s plan, the six tiers of tax rates would be simplified to two rates: 25 percent for higher earners and 10 percent for lower-earners. But the overall impact of the Ryan budget would still disproportionately benefit the wealthy. The top 20 percent would get a $13,907 tax cut in 2015, and the top 1 percent would get a whopping $155,808 tax break, according to an analysis by the Tax Policy Center. By contrast, the bottom 20 percent of Americans would pay $159 more in taxes in 2015.

That’s because the Ryan budget would get rid of tax breaks that benefit low-income Americans, including expansions of “the Earned Income Tax Credit, Child Tax Credit, and American Opportunity Tax Credit that were enacted in 2009,” according to the Center on Budget and Policy Priorities. As a result, effective tax rates on those with incomes than $30,000 would actually go up, while going down for the wealthy...