I believe this reply is spot on.
A delusion of grandeur manifests itself in the present tense.
Many here are confusing mere plans for the future (be they realistic or not), with a present over inflated sense of self worth, which may include delusions of grandeur.
At risk of Mod wrath, it would be fair to state: A President setting a lofty agenda for his administration, even if unrealistic, is not a delusion of grandeur. However, a President barely inaugurated, making the claim that he is already the greatest President in history… Well, THAT is a prime example of a person with delusions of grandeur.