You know how everyone is like "Oh dude, Obama totally got Trump at that press dinner!"
Well, I think about it kind of like a Silver Surfer comic. Usually Silver Surfer (the 2nd most powerful character in the Marvel universe) and Galactus (the most powerful character in the Marvel univers) just ignore humans. There's nothing humans can do to them. Their power is so grand, and what they think about is so beyond man, that humans are rarely a thought.
Its only once a human gets their attention that a human's worth is proved, and at that point you should start crapping your pants.
Just like Sarah Palin, the powers that be have judged Trump to be imporant enough to start attacking him. I'd wear it like a badge of pride if I was him. I'm sure he does.
And, like Trump says, Obama never bothered with the birth certificate until Trump started making noise about it. This just helps prove that Trump gets stuff done.
I hope he stays in the race and mixes it up, just for the sake of entertainment.