Future Charles Xavier: It is not their pain you are afraid of, it's yours, Charles. And as frightening as it may be, that pain will make you stronger, if you allow yourself to feel it, embrace it. It will make you more powerful than you ever imagined. It's the greatest gift we have, to bear their pain without breaking. And it's born from the most human power - hope. Please, Charles we need you to... Hope again.
Charles Xavier: I don't want your suffering! I don't want your future!
Logan: Look past my future, look for your future.
Professor Charles Xavier: Logan, I was a very different man. Lead me, guide me, be patient with me.
Logan: Patience isn't my strong suit.
Erik Lehnsherr: I didn't kill the President.
Charles Xavier: The bullet curved.
Erik Lehnsherr: I was trying to save him!
Charles Xavier: Why would you do that?
Erik Lehnsherr: Because he was one of us!
Magneto: All those years wasted fighting each other, Charles... For a precious few of them back.
Chosen answer: Government agents were previously aware of mutants - they are probably the same ones that imprisoned Magneto, and his attempt to prevent JFK's assassination was most likely covered up due to the revelation that Kennedy was a mutant. Magneto was already in prison by the time Trask pitched his Sentinel idea to the government, which is probably why the program wasn't instituted.
Phaneron ★