Based on what evidence? (crickets) no one in Congress - no one - is saying the BC is a forgery and calling for Obama's impeachment or at least some steps to ensure it never happens again. Not even all FReepers believe he is illegal. I am not so sure he is not a NBC EVEN if the BC is forged. There could be other things he is covering up.
I’ve seen surveys of public opinion that show most know he’s not playing straight with the public about his birth documents. It’s like man made carbon based global warming. The public knows when it is getting snowed sometimes.