I was reading up on Wikipedia about the history of Marine One. I was just curious about why the Marines flew the US President's helicopter. I mean, it's a no brainer that the Air Force flies his plane (still waiting on Sky Force One), but up until 1976, both Army and Marines jointly flew POTUS. Does anyone here know why that changed for Jimmy Carter? The quick googling I did show the Army has WAY more helicopters (~3000, over half of which are Black Hawks) than the Marines (~700). The President flies in the helicopter far more often from Land to Land, rather than Land to Sea and the Marine's are primarily focused on being an invasion force (or historically, ship's soldiers).

Does anyone here have any history or insight to this?

BTW, I don't have any chips in this game, I'm just curious (although my late brother was a Ranger and they Lead the Way!) TIA!

Edit: Did the end of Viet'Nam 3-years previous to the end of the Army ferrying the President contribute to it?