You might have heard, if you've been watching cable news at any point in the last 72 hours, that 47 percent of Americans will not owe income taxes this year. Conservatives argue that this is just one more way the economy is slipping into a social-egalitarian morass in which more Americans live off the productivity of the few elite who are actually busy putting the capital into capitalism. But if the 47% figure is a monster, it is also a monster that Republicans have helped to create.

To understand why that's true, it's important to understand why half of Americans aren't paying federal income taxes. Most of them receive generous tax credits -- the Earned Income Tax Credit (EITC), child-care credits, subsidies for college and savings -- worth more than their tax burden, according to the Tax Policy Center.

When Republicans rail against the 47% figure, they're railing against features like the EITC. What is the EITC? It's a refundable tax credit that rewards work and offsets the burden of payroll taxes for low-income payers by returning a fixed percent of income up to a maximum credit based on factors like number of children. But the EITC is a Republican creation. It was enacted in 1975 under President Ford (a Republican), and expanded numerous times over the last 35 years by Republicans. President Reagan (Republican) expanded it in 1984 and 1986. President Bush (Republican) expanded it against in 1990 and added supplemental credit for families with more than one child. President Clinton expanded it for childless claimants in 1993. President Bush (Republican) expanded it again in 2001.