So Trump posts this 2 times..

He spells "this is an historic"

Incorrect [N] 2 times....

Closing Act?

Technically "an historic" is correct even though it seems stupid.

In response Robert Wakefield to his Publication

Only people mentioned by @FightingIrishman in this post can reply

We share very few sentiments with our government.

In response FightingIrishman to his Publication

Was about to post the same thing. "An historic" is correct; "A historic" is not.