Jerry Seinfeld responded to Donald Trump's recent to do over President Obama's birth certificate, by pulling out of Trump's son's charity event. Jerry had signed on for a Sept 13th Eric Trump Foundation benefit aiding the St. Jude's Children's Research Hospital. Trump responds, read more and watch the video after the jump.The Donald, to say the least, a little fired up about Seinfeld's comments, fired off a nasty letter that was published in the New York Post. The video explains more.