which president had the highest iq?
098 - George Herbert Walker Bush. 091 - George Walker Bush. The six Republican presidents of the past 50 years had an average IQ of 115.5, with President Nixon having the highest at 155. President George W. Bush rated the lowest of all the Republicans with an IQ of 91. The six Democrat presidents had IQs with an average of 156, with President Clinton having the highest IQ, at 182. President Lyndon B. Johnson was rated the lowest of all the Democrats with an IQ of 126. No president other than Carter [D] has released his actual IQ (176).