Our new poll finds that Trump is benefiting from a GOP electorate that thinks Barack Obama is a Muslim and was born in another country, and that immigrant children should be deported. 66% of Trump’s supporters believe that Obama is a Muslim to just 12% that grant he’s a Christian. 61% think Obama was not born in the United States to only 21% who accept that he was. And 63% want to amend the Constitution to eliminate birthright citizenship, to only 20% who want to keep things the way they are ....
.... Trump’s beliefs represent the consensus among the GOP electorate. 51% overall want to eliminate birthright citizenship. 54% think President Obama is a Muslim. And only 29% grant that President Obama was born in the United States. That’s less than the 40% who think Canadian born Ted Cruz was born in the United States.
(Public Policy Polling; boldface accent added)
Public Policy Polling. Trump Supporters Think Obama is a Muslim Born in Another Country”. Press Release. 1 September 2015.