If you were Obama, and you COULD de-legitimize Trumps presidency, would you??

Methink it should be everyone's goal to expose the truth if it relates to the well being of the nation.

depends on what he was doing wrong

I believe Trump's election has already been delegitimized by the Russian hacking issue and by the almost 3 million voters who voted for Clinton.  I think he realizes tht, too.  Otherwise, he wouldn't have to begin each speech by reminding everyone by what a "YOOOGE" margin he won in the Electoral College.