Projected decline in total federal spending (relative to GDP), 2011-2023, under the Ryan budget plan unanimously supported by House Republicans (according to the Congressional Budget Office’s March 2012 report). Federal spending would fall from 22.5% of GDP in 2011 to 17.25% in 2023 (and to 15.5% in 2050, of which 10.75% would be for Social Security and Medicare).
Fraction of Americans who say the Republican Party is “generally more supportive of reducing the size and scope of the federal government” (according to the Pew Research Center’s April 2012 Knowledge Survey; 25% say the Democratic Party is more supportive of reducing the size and scope of government and 22% say they don’t know).
And political science in one number:
Google Scholar citations of Benjamin Page and Robert Shapiro’s The Rational Public.