If Trump's wiretapping claims are baseless, should Obama sue him for defamation?

Trump is immune to criminal charges but not from tort law. I would love to see it happen. As with Trump University, his best option would be to settle as soon as possible. That would be fine with me. That Obama is black and Trump is a racist would make it that much sweeter. Even better is that Trump made a stupid campaign statement about making libel laws tougher. Sweet irony!

Obama is a better person than I am and I doubt if he would bring a lawsuit.