I doubt that most Trump supporters know the meaning of pariah, Lawrence, but I think they will start to see its meaning as other nations begin to boycott American goods and services. After listening to and reading news and commentary from Europe, I think it's very likely there will be economic consequences if Trump actually does pull out of the Paris accord. Already even before this leaked information, tourism to the US was down. And people are already talking about boycotting American products. 
Actions have consequences.