Suppose for a minute that Trump is right and that Obama did wiretap Trump. What would Obama's motive have been?

I don’t believe the lunatic for a second.

But suppose it were true. What would Obama’s motive have been? What good would it have done to the administration?

I could see a possible (maybe) advantage to Clinton, but not to Obama. And I don’t see Obama passing intelligence to Clinton even if it were true.

My guess is that the FBI was tracking something criminal – like espionage by one of Trump’s advisors. And Trump being caught was just a happy coincidence.