The left-hand side shows the relationship between birther beliefs and Republicans’ evaluations of both Trump and then-House Speaker John A. Boehner (R-Ohio). As of April 2011, Republicans who said Obama was definitely not born in the United States rated Trump nearly 40 percentage points more favorably than Republicans who completely rejected birtherism. By contrast, birtherism was not closely linked to Republicans’ support for Boehner.

Boehner was actually more popular among Republicans in April 2011 than was Trump. Nevertheless, the strongest GOP birthers still rated Trump more than 20 points more favorably than the highest ranking Republican at that time, Boehner.

Birtherism also was significantly correlated with Republicans’ perceptions of how Trump would do as president. The right-hand graph shows that nearly half of the strongest birthers thought that he would make a good or great president. Only a quarter of Republicans who thought Obama was born in the United States believed that.

Meanwhile, birther beliefs were not correlated with Republicans’ perceptions of Romney’s potential performance as president.