Google "jfk gold standard" and you'll see tons of conspiracy theories on how JFK was sick of the decline in the USD and was planning to put us back on the full gold standard (And perhaps a dual silver standard too!) within months of his assassination.
Sadaam and Gaddafi both have more publicized plans of doing something similar in their countries.
Lincoln, of course, was already on the gold standard but to fund the war the powers that be created the "Greenback" (Which we used for 100 years afterwards) that was issued as debt, not as gold-backed, and lincoln didn't like that at all.
So they killed him, very cut and dry... We've been their puppets ever since.