Don’t start drifting.
This is EXACTLY the kind of mistake Trump has avoided.
Trump’s answer would have been something like: “Until Islam reforms in the way of other major religions have long ago and is able to separate religion from politics, I cannot support a Muslim for president.”
Of course Islam doesn’t see a need to reform, so his statement would have been a double-down, but with a further explanation and way for Islam (however futile) to get on his good side. But then Carson is no Trump.