Among the presumptive Democratic presidential nominee’s tax proposals is a plan to extend Social Security payroll taxes so they apply to income higher than $250,000.

In the video below, Dan Mitchell of the Cato Institute argues that change would increase the top marginal tax rate by about 12 percentage points. That’s a far larger hike than the 4.6 percentage-point increase tied to Sen. Barack Obama’s more highly publicized support for ending the 2003 Bush tax cuts.

Mitchell’s video ? distributed by the Center for Freedom and Prosperity ? suggests raising America?s top tax rate to French and German levels would undermine economic performance and reduce U.S. competitiveness.

Click here to learn more from Dan Mitchell about the way the economy works.