Research and studies have proven that Democrats are the usually the less intelligent of the 3 political parties.

DATA

Here is the data on education which is highly correlated with IQ:

Not HS Grad College Grad & Post-grad

% of Democrats 32% 15%

% of Independents 22% 18%

% of Republicans 19% 23%

Here is the data on people who earn incomes over $75,000 which is also highly correlated to IQ:

Income under $75,000 over $75,000

% of Democrats 74% 26%

% of Independents 72% 28%

% of Republicans 57% 43%

Many studies have been done on non-voters level of income and education; non-voters match independents exactly.  The Republican average IQ is higher than non-voters and independents and all three are higher than the Democratic average IQ.